View Filing Data

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	ACAD
Entity Registrant Name	ACADIA PHARMACEUTICALS INC
Entity Central Index Key	0001070494
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		124,701,944
Entity Public Float			$ 2.1

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 69,418	$ 163,620
Investment securities, available-for-sale	271,924	365,416
Accounts receivable, net	17,343	5,903
Interest and other receivables	1,087	1,237
Inventory	5,248	4,175
Prepaid expenses	8,457	7,546
Total current assets	373,477	547,897
Property and equipment, net	2,662	3,081
Intangible assets, net	5,538	7,015
Restricted cash	2,475	2,375
Other assets	354	785
Total assets	384,506	561,153
Liabilities and stockholders’ equity
Accounts payable	8,786	3,912
Accrued liabilities	40,244	36,029
Deferred revenue		2,644
Total current liabilities	49,030	42,585
Long-term liabilities	191	157
Total liabilities	49,221	42,742
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized at December 31, 2017 and 2016; no shares issued and outstanding at December 31, 2017 and 2016
Common stock, $0.0001 par value; 225,000,000 shares authorized at December 31, 2017 and December 31, 2016; 124,410,552 shares and 121,367,169 shares issued and outstanding at December 31, 2017 and December 31, 2016, respectively	12	12
Additional paid-in capital	1,559,343	1,452,272
Accumulated deficit	(1,223,671)	(933,979)
Accumulated other comprehensive (loss) income	(399)	106
Total stockholders’ equity	335,285	518,411
Total liabilities and stockholders’ equity	$ 384,506	$ 561,153

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	124,410,552	121,367,169
Common stock, shares outstanding	124,410,552	121,367,169

Consolidated Statements of Operations - USD ($)
shares in Thousands, $ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Revenues

Product sales, net

$ 124,901

$ 17,327

Collaborative revenue

$ 61

Total revenues

124,901

^[1]

17,331

^[1]

Operating expenses

Cost of product sales

9,077

3,075

License fees and royalties

3,983

1,331

2,500

Research and development

149,189

99,284

73,869

Selling, general and administrative

255,062

186,456

88,304

Total operating expenses

417,311

290,146

164,673

Loss from operations

(292,410)

(272,815)

(164,612)

Interest income, net

4,126

2,763

499

Loss before income taxes

(288,284)

(270,052)

(164,113)

Income tax expense

1,119

1,341

330

Net loss

$ (289,403)

$ (271,393)

$ (164,443)

Net loss per common share, basic and diluted

$ (2.36)

^[2]

$ (2.34)

^[2]

$ (1.63)

Weighted average common shares outstanding, basic and diluted

122,600

115,858

100,630

[1]	The Company commenced commercial sales of NUPLAZID in May 2016. The quarters after March 31, 2016 reflect net product revenue related to NUPLAZID.
[2]	Net loss per common share, basic and diluted, are computed independently for each quarter and the full year based upon respective average shares outstanding. Therefore, the sum of the quarterly net loss per common share amounts may not equal the annual amounts reported.

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (289,403)	$ (271,393)	$ (164,443)
Other comprehensive gain (loss):
Unrealized (loss) gain on investment securities	(499)	94	13
Foreign currency translation adjustments	(6)	1	7
Comprehensive loss	$ (289,908)	$ (271,298)	$ (164,423)

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net loss	$ (289,403,000)	$ (271,393,000)	$ (164,443,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	75,532,000	55,265,000	40,194,000
Amortization of premiums and accretion of discounts on investment securities	(291,000)	89,000	(2,060,000)
Amortization of intangible assets	1,477,000	985,000	0
Depreciation	1,236,000	843,000	647,000
Income tax benefit from exercise of stock options		(596,000)	(247,000)
Loss on disposal of assets	4,000	5,000
Changes in operating assets and liabilities:
Accounts receivable, net	(11,440,000)	(5,903,000)
Interest and other receivables	150,000	401,000	(674,000)
Inventory	(1,012,000)	(3,305,000)
Prepaid expenses and other current assets	(911,000)	(4,731,000)	(804,000)
Restricted cash	(100,000)	(2,000,000)	(375,000)
Other assets	431,000	(456,000)	(42,000)
Accounts payable	4,874,000	2,240,000	(344,000)
Accrued liabilities	4,206,000	15,579,000	6,256,000
Deferred revenue	(2,644,000)	2,644,000
Long-term liabilities	34,000	(75,000)	97,000
Net cash used in operating activities	(217,857,000)	(210,408,000)	(121,795,000)
Cash flows from investing activities
Purchases of investment securities	(478,818,000)	(683,355,000)	(269,486,000)
Maturities of investment securities	572,103,000	430,937,000	419,197,000
Intangible assets		(8,000,000)
Purchases of property and equipment	(812,000)	(1,506,000)	(2,141,000)
Net cash provided by (used in) investing activities	92,473,000	(261,924,000)	147,570,000
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	31,188,000	518,896,000	14,547,000
Proceeds from settlement agreement		14,320,000
Deferred offering costs			(292,000)
Income tax benefit from exercise of stock options		596,000	247,000
Net cash provided by financing activities	31,188,000	533,812,000	14,502,000
Effect of exchange rate changes on cash	(6,000)	2,000	7,000
Net (decrease) increase in cash and cash equivalents	(94,202,000)	61,482,000	40,284,000
Cash and cash equivalents at beginning of period	163,620,000	102,138,000	61,854,000
Cash and cash equivalents at end of period	69,418,000	163,620,000	102,138,000
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,367,000	365,000	415,000
Supplemental disclosure of noncash information:
Property and equipment purchases in accounts payable and accrued liabilities	9,000	220,000	$ 156,000
Stock-based compensation capitalized in inventory	$ (61,000)	$ 870,000

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2014	$ 309,489	$ 10	$ 807,631	$ (498,143)	$ (9)
Beginning balance (in shares) at Dec. 31, 2014		100,047,331
Issuance of common stock from exercise of stock options	12,991		12,991
Issuance of common stock from exercise of stock options (in shares)		1,822,578
Issuance of common stock pursuant to employee stock purchase plan	1,556		1,556
Issuance of common stock pursuant to employee stock purchase plan (in shares)		68,793
Income tax benefit from exercise of stock options	247		247
Deferred offering costs	(292)		(292)
Net loss	(164,443)			(164,443)
Stock-based compensation	40,194		40,194
Other comprehensive income (loss)	20				20
Ending balance at Dec. 31, 2015	199,762	$ 10	862,327	(662,586)	11
Ending balance (in shares) at Dec. 31, 2015		101,938,702
Issuance of common stock in public offering, net of issuance costs	497,765	$ 2	497,763
Issuance of common stock in public offering, net of issuance costs (in shares)		17,314,523
Issuance of common stock from exercise of stock options	18,000		18,000
Issuance of common stock from exercise of stock options (in shares)		1,977,661
Issuance of common stock pursuant to employee stock purchase plan	3,131		3,131
Issuance of common stock pursuant to employee stock purchase plan (in shares)		136,283
Income tax benefit from exercise of stock options	596		596
Proceeds from settlement agreement	14,320		14,320
Net loss	(271,393)			(271,393)
Stock-based compensation	56,135		56,135
Other comprehensive income (loss)	95				95
Ending balance at Dec. 31, 2016	518,411	$ 12	1,452,272	(933,979)	106
Ending balance (in shares) at Dec. 31, 2016		121,367,169
Issuance of common stock from exercise of stock options	$ 26,665		26,665
Issuance of common stock from exercise of stock options (in shares)	1,442,411	1,442,411
Issuance of common stock pursuant to employee stock purchase plan	$ 4,522		4,522
Issuance of common stock pursuant to employee stock purchase plan (in shares)		192,402
Issuance of common stock from exercise of warrants on a net issuance basis (in shares)	1,408,570	1,408,570
Net loss	$ (289,403)			(289,403)
Cumulative effect adjustment from adoption of ASU 2016-09	(289)			(289)
Stock-based compensation	75,884		75,884
Other comprehensive income (loss)	(505)				(505)
Ending balance at Dec. 31, 2017	$ 335,285	$ 12	$ 1,559,343	$ (1,223,671)	$ (399)
Ending balance (in shares) at Dec. 31, 2017		124,410,552

Organization and Business	12 Months Ended
Organization and Business	Dec. 31, 2017
Accounting Policies [Abstract]
Organization and Business	1. Organization and Business ACADIA Pharmaceuticals Inc. (the “Company”), based in San Diego, California, is a biopharmaceutical company focused on the development and commercialization of innovative medicines to address unmet medical needs in central nervous system disorders. The Company was originally incorporated in Vermont in 1993 as Receptor Technologies, Inc. and reincorporated in Delaware in 1997. On April 29, 2016, the U.S. Food and Drug Administration (“FDA”) approved the Company’s first drug, NUPLAZID^® (pimavanserin), for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis (“PD Psychosis”). NUPLAZID became available for prescription in the United States on May 31, 2016. Accordingly, the Company’s financial statements for 2017 and 2016 include product revenue and other transactions related to the commercialization of NUPLAZID that did not exist in prior years.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Significant accounting policies followed in the preparation of these financial statements are as follows:

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries located in Europe. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity date at the date of purchase of three months or less to be cash equivalents.

Investment Securities

The Company has classified all of its investment securities as available-for-sale as the sale of such securities may be required prior to maturity to implement management strategies, and accordingly, carries these investments at fair value. Unrealized gains and losses, if any, are reported as a separate component of stockholders’ equity. The cost of investment securities classified as available-for-sale is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses, if any, are also included in interest income. The cost of securities sold is based on the specific identification method.

Fair Value of Financial Instruments

The carrying values of the Company’s financial instruments, consisting of cash and cash equivalents, trade receivables, interest and other receivables, restricted cash, and accounts payable and accrued liabilities, approximate fair value due to the relative short-term nature of these instruments.

As disclosed in Note 4, the Company classifies its cash equivalents and available-for-sale investment securities within the fair value hierarchy as defined by authoritative guidance:

Level 1 Inputs	—	Quoted prices for identical instruments in active markets.

Level 2 Inputs	—	Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable.

Level 3 Inputs	—	Valuation derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.

Accounts Receivable

Accounts receivable are recorded net of customer allowances for distribution fees, prompt payment discounts, chargebacks, and doubtful accounts. Allowances for distribution fees, prompt payment discounts and chargebacks are based on contractual terms. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. At December 31, 2017, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented.

Inventory

Inventory, consisting of raw material and finished goods, is stated at the lower of cost or estimated net realizable value. The Company uses a combination of standard and actual costing methodologies to determine the cost basis for its inventories which approximates actual costs. Inventory is valued on a first-in, first-out basis and includes third-party manufacturing costs, freight, and indirect overhead costs. The Company capitalizes inventory costs associated with its products upon regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. Prior to FDA approval of NUPLAZID, all costs related to the manufacturing of NUPLAZID were charged to research and development expense in the period incurred. At December 31, 2017 the Company had an immaterial amount of zero-cost raw material that was available for use in the manufacturing of commercial product. The Company reduces its inventory to net realizable value for potentially excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand and any firm purchase orders, as well as product shelf life. During 2017, the Company recorded a charge of $0.7 million to reduce certain finished goods inventory to its net realizable value. No such charges were recorded in 2016 or 2015.

Property and Equipment

Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the term of the lease by use of the straight-line method. Construction-in-process reflects amounts incurred for property, equipment or improvements that have not been placed in service. Maintenance and repair costs are expensed as incurred. When assets are retired or sold, the assets and accumulated depreciation are removed from the respective accounts and any gain or loss is recognized.

Estimated useful lives by major asset category are as follows:

		Useful Lives
Machinery and equipment		5 to 7 years
Computers and software		3 years
Furniture and fixtures		10 years

Impairment of Long-Lived Assets

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Through December 31, 2017, no such impairment losses have been recorded by the Company.

License Fees and Royalties

The Company expenses amounts paid to acquire licenses associated with products under development when the ultimate recoverability of the amounts paid is uncertain and the technology has no alternative future use when acquired. Acquisitions of technology licenses are charged to expense or capitalized based upon management’s assessment regarding the ultimate recoverability of the amounts paid and the potential for alternative future use. The Company has determined that technological feasibility for its product candidates is reached when the requisite regulatory approvals are obtained to make the product available for sale.

In connection with the FDA approval of NUPLAZID in April 2016, the Company made a one-time milestone payment of $8.0 million pursuant to its 2006 license agreement with the Ipsen Group in which the Company licensed certain intellectual property rights that complement its patent portfolio for its serotonin platform, including NUPLAZID. The Company capitalized the $8.0 million payment as an intangible asset and is amortizing the asset on a straight-line basis over the estimated useful life of the licensed patents through the second half of 2021. The Company recorded amortization expense related to its intangible asset of $1.5 million and $1.0 million for the years ended December 31, 2017 and 2016, respectively. No such amortization was incurred during the year ended December 31, 2015. As of December 31, 2017, estimated future amortization expense related to the Company’s intangible asset was $1.5 million for each of 2018, 2019 and 2020, and $1.0 million for 2021.

Royalties incurred in connection with the Company’s license agreement with the Ipsen Group, as disclosed in Note 9, are expensed to license fees and royalties as revenue from product sales is recognized.

Advertising Expense

In connection with the FDA approval and commercial launch of NUPLAZID in 2016, the Company began to incur advertising costs. Advertising costs are expensed when services are performed or goods are delivered. The Company incurred $15.6 million and $1.6 million in advertising costs in 2017 and 2016, respectively, related to its marketed product, NUPLAZID. No advertising costs were capitalized as prepaid expenses at December 31, 2017 or 2016.

Revenue Recognition

Product Sales, Net

The Company’s net product sales consist of U.S. sales of NUPLAZID and are recognized when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred and title to the product and associated risk of loss has passed to the customer, (iii) the price is fixed or determinable, and (iv) collectability is reasonably assured.

NUPLAZID was approved by the FDA on April 29, 2016 and the Company commenced shipments of NUPLAZID to specialty pharmacies (“SPs”) and specialty distributors (“SDs”) in late May 2016. Prior to April 1, 2017, the Company deferred sales of NUPLAZID and recognized revenue when an SP dispensed product to a patient based on the fulfillment of a prescription and when an SD sold product to a government facility, long-term care pharmacy, or in-patient hospital pharmacy. In the second quarter of 2017 the Company determined that it had sufficient volume of activity to reasonably estimate its allowances for rebates and chargebacks and began recognizing NUPLAZID revenue, net of estimated allowances for rebates, price adjustments, returns, chargebacks, and prompt payment discounts, at the point of sale to the SPs and SDs which is commonly referred to as the “sell-in” revenue recognition model. As a result, the Company recorded a one-time adjustment during the three months ended June 30, 2017, to recognize deferred revenue on previously shipped product.

The effect on income from operations and on net income is that the Company is able to recognize revenue earlier on this sell-in method, net of a provision for estimated allowances, since the Company can record revenue once sold to the SP or SD rather than waiting until the product is sold to the end user on a sell-through basis, which it had done for periods prior to April 1, 2017.

Product shipping and handling costs are included in cost of product sales.

The Company recognizes revenue from product sales net of the following allowances and reflects each of these as either a reduction to the related account receivable or as an accrued liability, depending on how the allowance is settled:

Distribution Fees: Distribution fees include distribution service fees paid to the SPs and SDs based on a contractually fixed percentage of the wholesale acquisition cost (“WAC”), fees for data, and prompt payment discounts. Distribution fees are recorded as an offset to revenue based on contractual terms at the time revenue from the sale is recognized.

Rebates: Allowances for rebates include mandated discounts under the Medicaid Drug Rebate Program and the Medicare Part D prescription drug benefit. Rebates are amounts owed after the final dispensing of the product to a benefit plan participant and are based upon contractual agreements with, or statutory requirements pertaining to, Medicaid and Medicare benefit providers. The allowance for rebates is based on statutory discount rates and expected utilization. The Company’s estimates for expected utilization of rebates is based on historical data received from the SPs and SDs since product launch. Rebates are generally invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s activity, plus an accrual balance for prior quarters’ unpaid rebates. If actual future rebates vary from estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment.

Chargebacks: Chargebacks are discounts and fees that relate to contracts with government and other entities purchasing from the SDs at a discounted price. The SDs charge back to the Company the difference between the price initially paid by the SDs and the discounted price paid to the SDs by these entities. The Company also incurs group purchasing organization fees for transactions through certain purchasing organizations. The Company estimates sales with these entities and accrues for anticipated chargebacks and organization fees, based on the applicable contractual terms. If actual future chargebacks vary from these estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment.

Co-Payment Assistance: The Company offers co-payment assistance to commercially insured patients meeting certain eligibility requirements. Co-payment assistance is accrued for based on actual program participation and estimates of program redemption using data provided by third-party administrators.

Product Returns: Consistent with industry practice, the Company offers the SPs and SDs limited product return rights for damages, shipment errors, and expiring product; provided that the return is within a specified period around the product expiration date as set forth in the applicable individual distribution agreement. The Company does not allow product returns for product that has been dispensed to a patient. As the Company receives inventory reports from the SPs and SDs and has the ability to control the amount of product that is sold to the SPs and SDs, it is able to make a reasonable estimate of future potential product returns based on this on-hand channel inventory data and sell-through data obtained from the SPs and SDs. In arriving at its estimate, the Company also considers historical product returns, the underlying product demand, and industry data specific to the specialty pharmaceutical distribution industry.

Research and Development Expenses

Research and development expenses are charged to operations as incurred. Research and development expenses include, among other things, costs associated with services provided by contract organizations for preclinical development, pre-commercialization manufacturing expenses, and clinical trials. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or services provided and the invoices received from its external service providers. In the case of clinical trials, a portion of the estimated cost normally relates to the projected cost to treat a patient in the trials, and this cost is recognized based on the number of patients enrolled in the trial. Other indirect costs are generally recognized on a straight-line basis over the estimated period of the study. As actual costs become known, the Company adjusts its accruals accordingly.

Concentration Risk

Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash, cash equivalents, investment securities, accounts receivable, and restricted cash. The Company invests its excess cash primarily in a money market fund, U.S. Treasury notes, and high quality, marketable debt instruments of corporations and government sponsored enterprises in accordance with the Company’s investment policy. The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. All investment securities have a credit rating of at least A3/A- or better, or P-1/A-1 or better, as determined by Moody’s Investors Service or Standard & Poor’s. Further, the Company specifies credit quality standards for its customers that are designed to limit the Company’s credit exposure to any single party.

The Company does not currently have any of its own manufacturing facilities, and therefore it depends on an outsourced manufacturing strategy for the production of NUPLAZID for commercial use and for the production of its product candidates for clinical trials. The Company has contracts in place with two third-party manufacturers of drug product, one that is approved for the commercial production of NUPLAZID tablets and one that still requires approval for commercial production of capsules, and one third-party manufacturer of drug substance that is approved for the production of NUPLAZID active pharmaceutical ingredient (“API”). Although there are potential sources of supply other than the Company’s existing suppliers, any new supplier would be required to qualify under applicable regulatory requirements.

The Company has entered into distribution agreements with a limited number of SPs and SDs, and all of the Company’s product sales are to these customers. For the year ended December 31, 2017, the Company’s four largest customers represented approximately 89% of the Company’s product revenue and 87% of the Company’s accounts receivable balance at December 31, 2017. For the year ended December 31, 2016, the Company’s four largest customers represented approximately 93% of the Company’s product revenue and 91% of the Company’s accounts receivable balance at December 31, 2016.

Stock-Based Compensation

The fair value of each employee stock option and each employee stock purchase right granted is estimated on the grant date under the fair value method using the Black-Scholes valuation model. The estimated fair value of each stock option and purchase right is then expensed over the requisite service period, which is generally the vesting period. The following weighted-average assumptions were used during these periods:

	Years Ended December 31,
	2017			2016			2015
Stock Options:
Expected volatility		68	%		78	%		89	%
Risk-free interest rate		2	%	1-2		%		1-2	%
Expected dividend yield		0	%		0	%		0	%
Expected life of options in years		5.8			5.7			5.7

	Years Ended December 31,
	2017			2016			2015
Employee Stock Purchase Plan:
Expected volatility	44%-62		%	60%-77		%	51%-59		%
Risk-free interest rate	1.0%-1.7		%	0.4%-1.0		%	0.1%-0.9		%
Expected dividend yield		0	%		0	%		0	%
Expected life in years	0.5-2.0			0.5-2.0			0.5-2.0

Expected Volatility. The Company considers its historical volatility and implied volatility when determining the expected volatility.

Risk-Free Interest Rate. The Company determines its risk-free interest rate assumption based on the U.S. Treasury yield for obligations with contractual terms similar to the expected term of the stock option or purchase right being valued.

Expected Dividend Yield. The Company has never paid any dividends and currently has no plans to do so.

Expected Life. In determining the expected life for stock options, the Company considers, among other factors, its historical exercise experience to date as well as the mean time remaining to full vesting of all outstanding options and the mean time remaining to the end of the contractual term of all outstanding options. The estimated life for the Company’s employee stock purchase rights is based upon the terms of each offering period.

Stock-based awards issued to non-employees other than directors are accounted for under the fair value method using the Black-Scholes valuation model and are re-measured to fair value at each period end until the earlier of the date that performance by the non-employee is complete or a performance commitment has been obtained.

The table below summarizes the total stock-based compensation expense included in the Company’s statements of operations for the periods presented (in thousands):

	Years Ended December 31,
	2017		2016		2015
Cost of product sales	$	3,690	$	1,218	$	—
Research and development		26,485		18,050		12,171
Sales, general and administrative		45,357		35,997		28,023
	$	75,532	$	55,265	$	40,194

Stock-based compensation expense for the year ended December 31, 2015 included a one-time $9.0 million charge related to the transition agreement with the Company’s former Chief Executive Officer entered into in connection with his retirement from the Company in March 2015.

Income Taxes

Current income tax expense or benefit represents the amount of income taxes expected to be payable or refundable for the current year. A deferred income tax asset or liability is computed for the expected future impact of differences between the financial reporting and income tax bases of assets and liabilities and for the expected future tax benefit to be derived from tax credits and loss carryforwards. Deferred income tax expense or benefit represents the net change during the year in the deferred income tax asset or liability. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized.

The Company recognizes the impact of a tax position in the financial statements only if that position is more likely than not of being sustained upon examination by taxing authorities, based on the technical merits of the position. Any interest and penalties related to uncertain tax positions will be reflected in income tax expense.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, employee stock purchase rights, and warrants are considered to be common stock equivalents but are not included in the calculations of diluted net loss per share for the periods presented as their effect would be antidilutive. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities. More specifically, at December 31, 2017, 2016 and 2015, options, employee stock purchase rights, and warrants totaling approximately 18,526,000 shares, 14,739,000 shares and 11,525,000 shares, respectively, were excluded from the calculation of diluted net loss per share as their effect would have been anti-dilutive.

Segment Reporting

Management has determined that the Company operates in one business segment which is the development and commercialization of innovative medicines. All revenues for the years ended December 31, 2017, 2016 and 2015 were generated in the United States.

Recently Issued Accounting Standards

In November 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-18, Statement of Cash Flows: Restricted Cash, which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company has adopted this standard effective January 1, 2018. The adoption of this ASU will modify the Company’s current classification within the consolidated statement of cash flows but will not materially impact the Company’s consolidated financial statements.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, which changes the impairment model for most financial assets and certain other instruments. For trade receivables and other instruments, entities will be required to use a new forward-looking expected loss model that generally will result in the earlier recognition of allowances for losses. For available-for-sale debt securities with unrealized losses, the losses will be recognized as allowances rather than as reductions in the amortized cost of the securities. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted only as of annual reporting periods beginning after December 15, 2018. The Company is currently evaluating the timing and impact of the adoption of this guidance on the Company’s consolidated financial statements.

In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting, which is intended to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, classification on the statement of cash flows, and accounting for forfeitures. This guidance was effective for annual reporting periods beginning after December 15, 2016, including interim periods within those years. The Company adopted this guidance in the first quarter of 2017 using the modified retrospective transition method. Accordingly, the Company increased its deferred tax assets by $36.8 million, with a corresponding increase to its valuation allowance, to record previously unrecognized excess tax benefits. Additionally, the Company elected to make an accounting policy change to recognize forfeitures as they occur. As a result, the Company recorded an increase to additional paid-in capital and a corresponding increase to accumulated deficit of $0.3 million, respectively, to reflect the incremental stock-based compensation expense that would have been recognized in prior years pursuant to the modified guidance. Additionally, the Company increased its deferred tax assets by $0.1 million, with a corresponding increase to its valuation allowance, to record the excess tax benefit from the change.

In February 2016, the FASB issued ASU 2016-02, Leases, which requires a lessee to recognize a lease liability and a right-of-use asset for all leases with lease terms of more than 12 months. This guidance is effective for annual reporting periods beginning after December 15, 2018, including interim periods within those years, and early adoption is permitted. Companies are required to adopt this guidance using a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. As disclosed in Note 9, Commitments and Contingencies, the Company leases facilities under operating leases. While the Company is still evaluating the timing and impact of the adoption of this guidance on its consolidated financial statements, it anticipates that the adoption could result in an increase in the assets and liabilities recorded on its consolidated balance sheet.

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes nearly all existing revenue recognition guidance under generally accepted accounting principles. This ASU, as amended, is a comprehensive new revenue recognition model that requires an entity to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. This ASU also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. The original guidance was effective for annual reporting periods beginning after December 15, 2016. However, in July 2015, the FASB agreed to delay the effective date by one year, with early adoption permitted, but not before the original effective date of the standard. Companies may use either a full retrospective or a modified retrospective approach to adopt this guidance.

Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Topic 606 also impacts certain other areas, such as the accounting for costs to obtain or fulfill a contract. The standard also requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

The Company has adopted this standard effective January 1, 2018 using the modified-retrospective approach. Under this method the Company will apply the new standard to all new contracts initiated after the effective date, and, for contracts which have remaining obligations as of the effective date, will record an adjustment to the beginning balance of retained earnings. To date, the Company has assessed the effect of adoption of this standard as it relates to the Company’s one source of revenue: the sale of NUPLAZID to its customers. Based on the Company’s evaluation of the customer contracts governing these sales, the Company currently estimates that recognition of the Company’s revenue under the new standard will be materially consistent with the Company’s current revenue recognition policy, which uses the sell-in method. The Company also estimates there will not be a material impact to the beginning balance of retained earnings.

Investment Securities

12 Months Ended

Dec. 31, 2017

Investments Debt And Equity Securities [Abstract]

Investment Securities

3. Investment Securities

Investment securities, all classified as available-for-sale, consisted of the following (in thousands):

	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	32,976	$	—	$	(12	)	$	32,964
Government sponsored enterprise securities		10,082		—		(10	)		10,072
Corporate debt securities		138,650		1		(321	)		138,330
Commercial paper		90,623		—		(65	)		90,558
	$	272,331	$	1	$	(408	)	$	271,924

	December 31, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	82,484	$	6	$	(3	)	$	82,487
Government sponsored enterprise securities		73,789		1		(5	)		73,785
Corporate debt securities		79,190		—		(72	)		79,118
Commercial paper		129,861		165		—			130,026
	$	365,324	$	172	$	(80	)	$	365,416

At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, and the Company’s intent and ability to hold the investment until recovery of its amortized cost basis. The Company intends, and has the ability, to hold its investments in unrealized loss positions until their amortized cost basis has been recovered. Based on its evaluation, the Company determined that its unrealized losses were not other-than-temporary at December 31, 2017 and 2016.

The Company has classified all of its available-for-sale investment securities, including those with maturities beyond one year, as current assets on its consolidated balance sheets based on the highly liquid nature of the investment securities and because these investment securities are considered available for use in current operations. As of December 31, 2017, the Company held $48.7 million of available-for-sale investment securities with contractual maturity dates more than one year and less than two years. No securities with similar maturity dates were held as of December 31, 2016.

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

The Company’s investments include cash equivalents and available-for-sale investment securities consisting of a money market fund, U.S. Treasury notes, and high quality, marketable debt instruments of corporations and government sponsored enterprises in accordance with the Company’s investment policy. The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. All investment securities have a credit rating of at least A3/A- or better, or P-1/A-1 or better, as determined by Moody’s Investors Service or Standard & Poor’s.

The Company’s cash equivalents and available-for-sale investment securities are classified within the fair value hierarchy as defined by authoritative guidance. The Company’s investment securities classified as Level 1 are valued using quoted market prices. The Company obtains the fair value of its Level 2 financial instruments from third-party pricing services. The pricing services utilize industry standard valuation models whereby all significant inputs, including benchmark yields, reported trades, broker/dealer quotes, issuer spreads, bids, offers, or other market-related data, are observable. The Company validates the prices provided by the third-party pricing services by reviewing their pricing methods and matrices, and obtaining market values from other pricing sources. After completing the validation procedures, the Company did not adjust or override any fair value measurements provided by these pricing services as of December 31, 2017 and 2016, respectively.

The Company does not hold any securities classified as Level 3, which are securities valued using unobservable inputs. The Company has not transferred any investment securities between the classification levels.

The recurring fair value measurements of the Company’s cash equivalents and available-for-sale investment securities at December 31, 2017 and 2016 consisted of the following (in thousands):

			Fair Value Measurements at Reporting Date Using
	December 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	38,057	$	38,057	$	—	$	—
U.S. Treasury notes		32,964		32,964		—		—
Government sponsored enterprise securities		10,072		—		10,072		—
Corporate debt securities		154,396		—		154,396		—
Commercial paper		98,052		—		98,052		—
	$	333,541	$	71,021	$	262,520	$	—

			Fair Value Measurements at Reporting Date Using
	December 31, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	129,292	$	129,292	$	—	$	—
U.S. Treasury notes		82,487		82,487		—		—
Government sponsored enterprise securities		88,773		—		88,773		—
Corporate debt securities		82,857		—		82,857		—
Commercial paper		140,024		—		140,024		—
	$	523,433	$	211,779	$	311,654	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Details

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Details

5. Balance Sheet Details

Inventory consisted of the following (in thousands):

	December 31,
	2017		2016
Finished goods	$	1,164	$	2,355
Raw material		4,084		1,820
	$	5,248	$	4,175

Property and equipment, net, consisted of the following (in thousands):

	December 31,
	2017			2016
Machinery and equipment	$	1,076		$	1,087
Computers and software		2,868			2,718
Leasehold improvements		1,642			1,317
Furniture and fixtures		1,305			1,141
Construction-in-process		—			226
		6,891			6,489
Accumulated depreciation		(4,229	)		(3,408	)
	$	2,662		$	3,081

Depreciation of property and equipment was $1.2 million, $0.8 million, and $0.6 million for the years ended December 31, 2017, 2016, and 2015, respectively. During 2017, 2016 and 2015, the Company retired $0.4 million, $0.2 million, and $0.1 million, respectively, of fully depreciated property and equipment.

Accrued liabilities consisted of the following (in thousands):

	December 31,
	2017		2016
Accrued compensation and benefits	$	15,260	$	14,382
Accrued consulting and professional fees		9,395		9,488
Accrued research and development services		9,487		8,551
Accrued sales allowances		3,591		1,999
Other		2,511		1,609
	$	40,244	$	36,029

Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Stockholders' Equity

6. Stockholders’ Equity

Public Offerings

In August 2016, the Company raised net proceeds of approximately $215.9 million from the sale of 6,969,696 shares of its common stock in a follow-on public offering, including 909,090 shares sold pursuant to the exercise in full of the underwriters’ option to purchase additional shares.

In January 2016, the Company raised net proceeds of approximately $281.6 million from the sale of 10,344,827 shares of its common stock in a follow-on public offering. In connection with the January 2016 offering, the Company entered into a registration rights agreement (the “Registration Rights Agreement”) with 667, L.P., Baker Brothers Life Sciences, L.P. and 14159, L.P. (the “Baker Entities”), all of which are existing stockholders of the Company and are affiliated with two of its directors, Julian C. Baker and Dr. Stephen R. Biggar. Under the Registration Rights Agreement, the Company agreed that, if the Baker Entities demand that the Company register their shares of its common stock, par value $0.0001 per share, for resale under the Securities Act of 1933, as amended (the “Securities Act”), the Company would be obligated to effect such registration. The Company’s registration obligations under the Registration Rights Agreement cover all shares of its common stock now held or later acquired by the Baker Entities (including approximately $75.0 million and $43.0 million of shares that the Baker Entities purchased at the public offering price in the January 2016 and August 2016 offerings, respectively), will continue in effect for up to 10 years, and include the Company’s obligation to facilitate certain underwritten public offerings of its common stock by the Baker Entities in the future. The Company has agreed to bear all expenses incurred by it in effecting any registration pursuant to the Registration Rights Agreement as well as the legal expenses of the Baker Entities of up to $50,000 per underwritten public offering effected pursuant to the Registration Rights Agreement. On April 1, 2016, pursuant to the Registration Rights Agreement, the Company filed a registration statement covering all shares owned by the Baker Entities as of March 31, 2016.

Private Equity Financings

In December 2012, the Company raised net proceeds of $80.5 million through the sale of 19,000,000 shares of its common stock at a price of $4.43 per share and the sale of warrants to purchase 500,000 shares of its common stock at a price of $4.42 per warrant share in a private equity financing. The warrants have an exercise price of $0.01 per share and will expire on December 17, 2019. In accordance with authoritative accounting guidance, the warrants’ value of $2.2 million was determined on the date of grant using the Black-Scholes model with the following assumptions: risk free interest rate of 1.1 percent, volatility of 105.8 percent, a 7.0 year term and no dividend yield. These warrants were recorded as a component of stockholders’ equity within additional paid-in capital. Per their terms, the warrants to purchase 500,000 shares of common stock, all of which remained outstanding at December 31, 2017, may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99 percent following such exercise.

In January 2011, the Company raised net proceeds of $13.9 million through the sale of 12,565,446 units at a price of $1.19375 per unit in a private equity financing. Each unit consisted of one share of the Company’s common stock and a warrant to purchase 0.35 shares of common stock. The warrants had an exercise price of $1.38 per share and an expiration date of January 11, 2018. In accordance with authoritative accounting guidance, the warrants’ value of $3.3 million was determined on the date of grant using the Black-Scholes model with the following assumptions: risk free interest rate of 2.8 percent, volatility of 99.0 percent, a 7.0 year term and no dividend yield. These warrants were recorded as a component of stockholders’ equity with an equal offsetting amount to stockholders’ equity because the value of the warrants was considered a financing cost. During the year ended December 31, 2017, warrants to purchase 1,465,968 shares of common stock were exercised on a net issuance basis, resulting in the issuance of 1,408,570 shares of common stock. During the year ended December 31, 2013, warrants to purchase 1,759,162 shares of common stock were exercised on a net issuance basis, resulting in the issuance of 1,643,006 shares of common stock. During the year ended December 31, 2012, warrants to purchase 1,172,774 shares of common stock were exercised on a net issuance basis, resulting in the issuance of 874,719 shares of common stock. At December 31, 2017, no warrants to purchase shares of common stock remained outstanding.

Stock Option Plans

The Company’s 2010 Equity Incentive Plan, as amended to date (the “2010 Plan”), permits the grant of options to employees, directors and consultants. In addition, the 2010 Plan permits the grant of stock bonuses, rights to purchase restricted stock, and other stock awards. The exercise price of options granted under the 2010 Plan cannot be less than 100 percent of the fair market value of the common stock on the date of grant and the maximum term of any option is 10 years. Options granted under the 2010 Plan generally vest over a four-year period. All shares that remained eligible for grant under the Company’s 2004 Equity Incentive Plan (the “2004 Plan”) at the time of approval of the 2010 Plan were transferred to the 2010 Plan. The 2010 Plan share reserve also has been, and may be, increased by the number of shares that otherwise would have reverted to the 2004 Plan reserve after June 2010. In June 2015, June 2016, and June 2017, the Company’s stockholders approved amendments to its 2010 Plan to, among other things, increase the aggregate number of shares of common stock authorized for issuance under the plan by 5,000,000 shares, 3,000,000 shares, and 5,500,000 shares respectively, and at December 31, 2017, there were 25,997,247 shares of common stock authorized for issuance, of which 8,053,811 shares were available for new grants under the 2010 Plan.

The 2004 Plan provided for the grant of options to employees, directors and consultants. The exercise price of options granted under the 2004 Plan was at 100 percent of the fair market value of the common stock on the date of grant and the maximum term of any option was 10 years. Options granted under the 2004 Plan generally vested over a four-year period.

Stock option transactions during the year ended December 31, 2017 are presented below:

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2016		12,743,877		$	26.41
Granted		7,867,683		$	34.73
Exercised		(1,442,411	)	$	18.49
Cancelled/forfeited		(1,225,713	)	$	30.48
Outstanding at December 31, 2017		17,943,436		$	30.42		8.1	$	55,794
Vested and expected to vest at December 31, 2017		17,943,436		$	30.42		8.1	$	55,794
Exercisable at December 31, 2017		6,464,292		$	26.07		6.6	$	41,449

The aggregate intrinsic value of options exercisable as of December 31, 2017 is calculated as the difference between the exercise price of the underlying options and the closing market price of the Company’s common stock on that date, which was $30.11 per share. The aggregate intrinsic value of options exercised during the years ended December 31, 2017, 2016, and 2015 was approximately $24.4 million, $43.2 million, and $55.9 million, respectively, determined as of the date of exercise. The Company received $26.7 million in cash from options exercised during the year ended December 31, 2017.

The weighted average per share fair value of options granted during the years ended December 31, 2017, 2016, and 2015 was approximately $21.11, $17.65, and $25.80, respectively. As of December 31, 2017, total unrecognized compensation cost related to stock options and purchase rights was approximately $206.5 million, and the weighted average period over which this cost is expected to be recognized is approximately 3.19 years.

Employee Stock Purchase Plan

The Company’s 2004 Employee Stock Purchase Plan (the “Purchase Plan”) became effective upon the closing of the Company’s initial public offering in June 2004. The Purchase Plan included an “evergreen” provision providing that a limited number of additional shares may be added to the shares authorized for issuance on the date of each annual meeting of stockholders for a period of 10 years, which ended with the meeting in 2014. In June 2016, the Company’s stockholders approved an amendment to the Purchase Plan to, among other things, increase the aggregate number of shares of common stock authorized for issuance under the plan by 400,000 shares, and at December 31, 2017, a total of 1,925,000 shares of common stock had been reserved for issuance under the Purchase Plan. At December 31, 2017, 388,011 shares of common stock remained available for issuance pursuant to the Purchase Plan. Eligible employees who elect to participate in an offering under the Purchase Plan may have up to 15 percent of their earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the Purchase Plan. The price of common stock purchased under the Purchase Plan is equal to 85 percent of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant purchase date. During the years ended December 31, 2017, 2016, and 2015, a total of 192,402, 136,283, and 68,793 shares of common stock were issued under the Purchase Plan at average per share prices of $23.50, $22.97, and $22.62, respectively. The weighted average per share fair value of purchase rights granted during the years ended December 31, 2017, 2016, and 2015 was $11.44, $12.34, and $14.31, respectively. During the years ended December 31, 2017, 2016, and 2015, the Company recorded cash received from the exercise of purchase rights of $4.5 million, $3.1 million, and $1.6 million, respectively.

Settlement Agreement Proceeds

In April 2016, the Company received a payment of $14.3 million pursuant to a settlement agreement with prior 10% stockholders who sold shares of the Company’s stock in 2013 that may have resulted in short-swing profits by the stockholders pursuant to Section 16(b) of the Securities Exchange Act of 1934, as amended. The Company recognized these proceeds as a capital contribution from stockholders and reflected a corresponding increase to additional paid-in capital.

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
401(k) Plan	7. 401(k) Plan Effective January 1997, the Company established a deferred compensation plan (the “401(k) Plan”) pursuant to Section 401(k) of the Internal Revenue Code of 1986, as amended (the “Code”), whereby substantially all employees are eligible to contribute up to 60 percent of their pretax earnings, not to exceed amounts allowed under the Code. The Company makes discretionary contributions to the 401(k) Plan equal to 100 percent of each employee’s pretax contributions up to 5 percent of his or her eligible compensation, subject to limitations under the Code. The Company’s total contributions to the 401(k) Plan were $3.3 million, $2.1 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

8. Income Taxes

Domestic and foreign pre-tax income (loss) is as follows (in thousands):

	Years Ended December 31,
	2017			2016			2015
Domestic		(45,249	)	$	(18,419	)	$	25,854
Foreign		(243,035	)		(251,633	)		(189,967	)
		(288,284	)	$	(270,052	)	$	(164,113	)

At December 31, 2017, the Company had federal, state, and foreign net operating loss (“NOL”) carryforwards of approximately $407.1 million, $340.0 million, and $647.4 million, respectively. The Company recognized state income tax provisions of $1.1 million, $1.3 million and $0.3 million for the years ended December 31, 2017, 2016 and 2015, respectively. These tax liabilities were associated with California state alternative minimum tax obligations and the apportionment of income to certain state jurisdictions in which the Company did not have corresponding NOLs. Utilization of the domestic NOL and research and development (“R&D”) credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred or that could occur in the future, as required by Section 382 of the Code, as well as similar state and foreign provisions. These ownership changes may limit the amount of NOL and R&D credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an “ownership change” as defined by Section 382 of the Code results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50 percentage points of the outstanding stock of a company by certain stockholders or public groups.

The Company previously completed a study to assess whether an ownership change, as defined by Section 382 of the Code, had occurred from the Company’s formation through December 31, 2013. Based upon this study, the Company determined that several ownership changes had occurred. Accordingly, the Company reduced its deferred tax assets related to the federal NOL carryforwards and the federal R&D credit carryforwards that are anticipated to expire unused as a result of these ownership changes. These tax attributes were excluded from deferred tax assets with a corresponding reduction of the valuation allowance with no net effect on income tax expense or the effective tax rate. The Company completed a study through December 31, 2017 and concluded no additional ownership changes occurred. Future ownership changes may further limit the Company’s ability to utilize its remaining tax attributes.

Federal and state NOL carryforwards of $2.3 million and less than $0.1 million will expire in 2018, respectively, unless utilized. The remaining federal and state NOL carryforwards will begin to expire in 2023. At December 31, 2017, the Company had $19.8 million of federal R&D credit carryforwards of which $0.1 million will expire in 2018 unless utilized, and the remaining federal R&D credit carryforwards will begin to expire in 2019. At December 31, 2017, the Company had state R&D credit carryforwards of approximately $0.2 million that will begin to expire in 2023 and $10.0 million that have no expiration date. At December 31, 2017, the Company had foreign NOL carryforwards of approximately $643.9 million that will expire in 2022 and $3.6 million that have no expiration date. The Company continues to record the deferred tax assets related to these attributes, subject to valuation allowance, until expiration occurs.

Prior to the issuance of ASU No. 2016-09, entities were required to recognize excess tax benefit or deficiency as additional paid-in capital. To simplify the presentation of stock compensation, the amendments in this ASU require that the excess tax benefit or deficiency is recognized as expense. For public business entities, the amendments in this ASU are effective for financial statements issued for annual periods beginning after December 15, 2016 and interim periods within those annual periods. The Company adopted the update as of January 1, 2017. Given the Company's full valuation position there is no quantitative impact to the financial statements.

The components of the deferred tax assets are as follows (in thousands):

	December 31,
	2017			2016
NOL carryforwards	$	163,059		$	168,753
R&D credit carryforwards		27,862			21,016
Capitalized R&D		5,606			3,977
Stock-based compensation		30,986			27,576
Other		10,110			6,102
		237,623			227,424
Valuation allowance		(237,623	)		(227,424	)
	$	—		$	—

Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by approximately $10.2 million in 2017 primarily due to an increase in deferred tax assets generated from net operating losses, R&D credits and stock-based compensation expense, partially offset by the expiration of NOL carryforwards in 2017 and the remeasurement of our deferred tax balance for changes in future tax rates.

On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was signed into legislation. At December 31, 2017, the Company has not yet completed its accounting assessment for the tax effects of the enactment of the Act; however, as described below, the Company has made a reasonable estimate of the effects on the existing deferred tax balances.

As a result of the lower enacted corporate tax rate, the Company has remeasured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. The provisional amount recorded related to the remeasurement of the Company’s deferred tax balance was $68.9 million, that is fully offset by a corresponding decrease to the valuation allowance.

On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of US GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, the Company has provisionally determined that there is no deferred tax benefit or expense with respect to the remeasurement of certain deferred tax assets and liabilities due to the full valuation allowance against net deferred tax assets. The Company is still analyzing certain aspects of the Act and refining its calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. Additional analysis of the law and the impact to the Company will be performed and any impact will be recorded in the respective quarter in 2018.

A reconciliation of income taxes to the amount computed by applying the statutory federal income tax rate to the pretax loss is summarized as follows (in thousands):

	Years Ended December 31,
	2017			2016			2015
Amounts computed at statutory federal rate	$	(98,016	)	$	(91,818	)	$	(55,799	)
Stock-based compensation and other permanent differences		1,341			3,065			1,752
R&D credits		(5,573	)		(3,390	)		(3,782	)
Change in valuation allowance		(28,230	)		27,583			4,580
State taxes		(26	)		272			742
Contingencies		360			361			2,247
Foreign rate differential		61,480			64,065			48,456
Tax Cuts and Jobs Act		68,889			—			—
Other		894			1,203			2,134
Income tax expense	$	1,119		$	1,341		$	330

The tax years 1998-2016 remain open to examination by the major taxing jurisdictions to which the Company is subject.

The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination. The Company recorded an uncertain tax position reserve of $0.4 million, $0.4 million and $2.3 million for the years ended December 31, 2017, 2016 and 2015, respectively. In addition, due to the Tax Cuts and Jobs Act a provisional adjustment of $1.1 million was made to remeasure the uncertain tax position reserve at December 31, 2017. Due to the valuation allowance recorded against the Company’s deferred tax assets, an immaterial amount of the total unrecognized tax benefits as of December 31, 2017 would reduce the annual effective tax rate if recognized. The Company does not anticipate that the amount of unrecognized tax benefits as of December 31, 2017 will significantly change within the next twelve months. The Company’s practice is to recognize interest and/or penalties related to uncertain income tax positions in income tax expense. The Company had no interest and/or penalties accrued on the Company’s consolidated balance sheets at December 31, 2017 or 2016, respectively. Further, the Company did not recognize any interest and/or penalties in the statement of operations for the years ended December 31, 2017, 2016 and 2015, respectively, related to uncertain tax positions.

The following table provides a reconciliation of changes in unrecognized tax benefits (in thousands):

	Years Ended December 31,
	2017			2016		2015
Balance at beginning of period	$	2,664		$	2,301	$	—
Additions related to current period tax positions		361			363		2,301
Provisional impact of Tax Cuts and Jobs Act		(1,092	)		—		—
Balance at end of period	$	1,933		$	2,664	$	2,301

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

Leases and Other Long-Term Commitments

The Company leases facilities and certain equipment under noncancelable operating leases that expire at various dates through May 2020. Under the terms of the facilities leases, the Company is required to pay its proportionate share of property taxes, insurance and normal maintenance costs. Rent expense for operating leases is recorded on a straight-line basis over the life of the lease term. If an operating lease contains fixed and determinable escalation clauses, the difference between the rent expense and the rent paid is recorded as deferred rent. Rent expense under the Company’s facility and equipment leases was $3.8 million, $2.8 million, and $2.9 million, for the years ended December 31, 2017, 2016, and 2015, respectively.

In 2015, the Company entered into a master lease agreement giving the Company the ability to lease vehicles under operating leases with initial terms of 36 months from the date of delivery. In connection with this lease agreement, the Company has established a letter of credit for $0.5 million, which has automatic annual extensions and is fully secured by restricted cash.

The Company also enters into certain other long-term commitments for goods and services that are outstanding for periods greater than one year. To the extent these long-term commitments are noncancelable, they are reflected in the table below.

Estimated annual future minimum payments related to the Company’s operating leases were as follows at December 31, 2017 (in thousands):

2018	$	2,529
2019		1,019
2020		320
2021		—
2022		—
Thereafter		—
	$	3,868

The Company also enters into short-term agreements with various vendors and suppliers of goods and services in the normal course of operations through purchase orders or other documentation, or that are undocumented except for an invoice. Such short-term agreements are generally outstanding for periods less than a year and are settled by cash payments upon delivery of goods and services. The nature of the work being conducted under these agreements is such that, in most cases, the services may be stopped on short notice. In such event, the Company would not be liable for the full amount of the agreement and are therefore not reflected in the above table.

Royalty Payments

Pursuant to the terms of its 2006 license agreement with the Ipsen Group, the Company is required to make royalty payments of two percent of net sales of NUPLAZID.

Corporate Credit Card Program

In connection with the Company’s credit card program, the Company established a letter of credit in 2016 for $2.0 million, which has automatic annual extensions and is fully secured by restricted cash.

Legal Proceedings

In March 2015, following the Company’s announcement of the update to the timing of its planned NDA submission to the FDA for NUPLAZID for the treatment of PD Psychosis and the subsequent decline of the price of its common stock, two putative securities class action complaints (captioned Rihn v. ACADIA Pharmaceuticals Inc., Case No. 15-cv-0575-BTM-DHB, and Wright v. ACADIA Pharmaceuticals Inc., Case No. 15-cv-0593- BTM-DHB) were filed in the U.S. District Court for the Southern District of California (the “Court”) against the Company and certain of its current and former officers. The complaints generally alleged that the defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 by making materially false and misleading statements regarding the timing of the Company’s planned NDA submission to the FDA for NUPLAZID, thereby artificially inflating the price of its common stock. The complaints sought unspecified monetary damages and other relief. On April 10 and June 1, 2015, the Court entered orders deferring the defendants’ response to the Rihn and Wright complaints until after the Court appointed a lead plaintiff and assigned lead counsel. On May 12, 2015, several putative stockholders filed separate motions to consolidate the two actions and be appointed lead plaintiff. On September 8, 2015, the Court issued an order consolidating the two actions, appointing lead plaintiffs, and assigning lead counsel. On November 16, 2015, lead plaintiffs filed a consolidated complaint with the Court which, like the prior complaints, accuses the defendants of making materially false and misleading statements regarding the anticipated timing of the Company’s planned NDA submission to the FDA for NUPLAZID. On January 15, 2016, the defendants filed a motion to dismiss the consolidated complaint. On September 19, 2016, the Court issued an order denying the motion to dismiss the consolidated complaint. On December 6, 2016, the parties had a mediation and agreed in principle to settle the action. On March 13, 2017, the parties signed a Stipulation of Settlement setting forth the terms of the proposed settlement. On June 9, 2017, the Court preliminarily approved the settlement (the “Preliminary Approval Order”). Among other things, the Preliminary Approval Order set an opt-out deadline of August 29, 2017; an objection deadline of September 13, 2017; and a final approval hearing for October 3, 2017. On August 29, 2017, lead plaintiffs filed a motion for final approval of the settlement and a motion for attorneys’ fees and expenses (the “Final Approval Motions”). On October 3, 2017, the Court continued the hearing so that, among other things, lead plaintiffs could submit additional documents in support of final approval. On January 22, 2018, the Court issued an order granting the Final Approval Motions and entered final judgment in the consolidated action.

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

10. Selected Quarterly Financial Data (Unaudited)

The following financial information reflects all normal recurring adjustments, which are, in the opinion of management, necessary for a fair statement of the results of the interim periods. Summarized quarterly data for the years ended December 31, 2017 and 2016 are as follows (in thousands, except per share data):

	Fiscal Year 2017 Quarters
	1st			2nd			3rd			4th			Total
Revenues⁽¹⁾	$	15,286		$	30,475		$	35,578		$	43,562		$	124,901
Gross profit⁽²⁾	$	13,023		$	28,251		$	33,443		$	41,107		$	115,824
Net loss	$	(87,843	)	$	(67,441	)	$	(65,248	)	$	(68,871	)	$	(289,403	)
Basic and diluted net loss per share⁽³⁾	$	(0.72	)	$	(0.55	)	$	(0.53	)	$	(0.55	)	$	(2.36	)

	Fiscal Year 2016 Quarters
	1st			2nd			3rd			4th			Total
Revenues⁽¹⁾	$	4		$	97		$	5,268		$	11,962		$	17,331
Gross profit⁽²⁾	$	—		$	(429	)	$	4,423		$	10,258		$	14,252
Net loss	$	(49,762	)	$	(71,322	)	$	(71,613	)	$	(78,696	)	$	(271,393	)
Basic and diluted net loss per share⁽³⁾	$	(0.45	)	$	(0.63	)	$	(0.61	)	$	(0.65	)	$	(2.34	)

⁽¹⁾	The Company commenced commercial sales of NUPLAZID in May 2016. The quarters after March 31, 2016 reflect net product revenue related to NUPLAZID.

⁽²⁾	Determined by subtracting cost of product sales from product sales, net.

⁽³⁾	Net loss per common share, basic and diluted, are computed independently for each quarter and the full year based upon respective average shares outstanding. Therefore, the sum of the quarterly net loss per common share amounts may not equal the annual amounts reported.

SCHEDULE II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2017

Valuation And Qualifying Accounts [Abstract]

SCHEDULE II - Valuation and Qualifying Accounts

SCHEDULE II – Valuation and Qualifying Accounts

(in thousands)

			Additions		Deductions
	Balance at Beginning of Period		Provision Related to Current Period Sales		Actual Distribution Fees, Discounts and Chargebacks Related to Current Period Sales			Actual Distribution Fees, Discounts and Chargebacks Related to Prior Period Sales			Balance at End of Period
Allowance for distribution fees, discounts and chargebacks:
For the year ended December 31, 2016	$	—	$	2,163	$	(1,962	)	$	—		$	201
For the year ended December 31, 2017	$	201	$	12,837	$	(12,591	)	$	(201	)	$	246

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Principles of Consolidation

Use of Estimates

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity date at the date of purchase of three months or less to be cash equivalents.

Investment Securities

Fair Value of Financial Instruments

As disclosed in Note 4, the Company classifies its cash equivalents and available-for-sale investment securities within the fair value hierarchy as defined by authoritative guidance:

Level 1 Inputs	—	Quoted prices for identical instruments in active markets.

Level 2 Inputs	—	Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable.

Level 3 Inputs	—	Valuation derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable.

Accounts Receivable

Inventory

Property and Equipment

Estimated useful lives by major asset category are as follows:

		Useful Lives
Machinery and equipment		5 to 7 years
Computers and software		3 years
Furniture and fixtures		10 years

Impairment of Long-Lived Assets

License Fees and Royalties

Advertising Expense

Revenue Recognition

Product Sales, Net

Product shipping and handling costs are included in cost of product sales.

Research and Development Expenses

Concentration Risk

Stock-Based Compensation

	Years Ended December 31,
	2017			2016			2015
Stock Options:
Expected volatility		68	%		78	%		89	%
Risk-free interest rate		2	%	1-2		%		1-2	%
Expected dividend yield		0	%		0	%		0	%
Expected life of options in years		5.8			5.7			5.7

	Years Ended December 31,
	2017			2016			2015
Employee Stock Purchase Plan:
Expected volatility	44%-62		%	60%-77		%	51%-59		%
Risk-free interest rate	1.0%-1.7		%	0.4%-1.0		%	0.1%-0.9		%
Expected dividend yield		0	%		0	%		0	%
Expected life in years	0.5-2.0			0.5-2.0			0.5-2.0

Expected Volatility. The Company considers its historical volatility and implied volatility when determining the expected volatility.

Expected Dividend Yield. The Company has never paid any dividends and currently has no plans to do so.

The table below summarizes the total stock-based compensation expense included in the Company’s statements of operations for the periods presented (in thousands):

	Years Ended December 31,
	2017		2016		2015
Cost of product sales	$	3,690	$	1,218	$	—
Research and development		26,485		18,050		12,171
Sales, general and administrative		45,357		35,997		28,023
	$	75,532	$	55,265	$	40,194

Income Taxes

Net Loss Per Share

Segment Reporting

Recently Issued Accounting Standards

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of Estimated Useful Lives by Major Asset Category

Estimated useful lives by major asset category are as follows:

		Useful Lives
Machinery and equipment		5 to 7 years
Computers and software		3 years
Furniture and fixtures		10 years

Weighted-Average Assumptions Used to Estimate Fair Value of Employee Stock Options

The estimated fair value of each stock option and purchase right is then expensed over the requisite service period, which is generally the vesting period. The following weighted-average assumptions were used during these periods:

	Years Ended December 31,
	2017			2016			2015
Stock Options:
Expected volatility		68	%		78	%		89	%
Risk-free interest rate		2	%	1-2		%		1-2	%
Expected dividend yield		0	%		0	%		0	%
Expected life of options in years		5.8			5.7			5.7

Weighted-Average Assumptions Used to Estimate Fair Value of Employee Stock Purchase Plan Rights

	Years Ended December 31,
	2017			2016			2015
Employee Stock Purchase Plan:
Expected volatility	44%-62		%	60%-77		%	51%-59		%
Risk-free interest rate	1.0%-1.7		%	0.4%-1.0		%	0.1%-0.9		%
Expected dividend yield		0	%		0	%		0	%
Expected life in years	0.5-2.0			0.5-2.0			0.5-2.0

Summary of Stock-based Compensation Expense Included in Statements of Operations

The table below summarizes the total stock-based compensation expense included in the Company’s statements of operations for the periods presented (in thousands):

	Years Ended December 31,
	2017		2016		2015
Cost of product sales	$	3,690	$	1,218	$	—
Research and development		26,485		18,050		12,171
Sales, general and administrative		45,357		35,997		28,023
	$	75,532	$	55,265	$	40,194

Investment Securities (Tables)

12 Months Ended

Dec. 31, 2017

Investments Debt And Equity Securities [Abstract]

Schedule of Investment Securities Classified as Available-for-Sale

Investment securities, all classified as available-for-sale, consisted of the following (in thousands):

	December 31, 2017
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	32,976	$	—	$	(12	)	$	32,964
Government sponsored enterprise securities		10,082		—		(10	)		10,072
Corporate debt securities		138,650		1		(321	)		138,330
Commercial paper		90,623		—		(65	)		90,558
	$	272,331	$	1	$	(408	)	$	271,924

	December 31, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	82,484	$	6	$	(3	)	$	82,487
Government sponsored enterprise securities		73,789		1		(5	)		73,785
Corporate debt securities		79,190		—		(72	)		79,118
Commercial paper		129,861		165		—			130,026
	$	365,324	$	172	$	(80	)	$	365,416

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements of Cash Equivalents and Available-For-Sale Investment Securities

The recurring fair value measurements of the Company’s cash equivalents and available-for-sale investment securities at December 31, 2017 and 2016 consisted of the following (in thousands):

			Fair Value Measurements at Reporting Date Using
	December 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	38,057	$	38,057	$	—	$	—
U.S. Treasury notes		32,964		32,964		—		—
Government sponsored enterprise securities		10,072		—		10,072		—
Corporate debt securities		154,396		—		154,396		—
Commercial paper		98,052		—		98,052		—
	$	333,541	$	71,021	$	262,520	$	—

			Fair Value Measurements at Reporting Date Using
	December 31, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	129,292	$	129,292	$	—	$	—
U.S. Treasury notes		82,487		82,487		—		—
Government sponsored enterprise securities		88,773		—		88,773		—
Corporate debt securities		82,857		—		82,857		—
Commercial paper		140,024		—		140,024		—
	$	523,433	$	211,779	$	311,654	$	—

Balance Sheet Details (Tables)

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Inventory

Inventory consisted of the following (in thousands):

	December 31,
	2017		2016
Finished goods	$	1,164	$	2,355
Raw material		4,084		1,820
	$	5,248	$	4,175

Property and Equipment, Net

Property and equipment, net, consisted of the following (in thousands):

	December 31,
	2017			2016
Machinery and equipment	$	1,076		$	1,087
Computers and software		2,868			2,718
Leasehold improvements		1,642			1,317
Furniture and fixtures		1,305			1,141
Construction-in-process		—			226
		6,891			6,489
Accumulated depreciation		(4,229	)		(3,408	)
	$	2,662		$	3,081

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	December 31,
	2017		2016
Accrued compensation and benefits	$	15,260	$	14,382
Accrued consulting and professional fees		9,395		9,488
Accrued research and development services		9,487		8,551
Accrued sales allowances		3,591		1,999
Other		2,511		1,609
	$	40,244	$	36,029

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Stock Option Transactions

Stock option transactions during the year ended December 31, 2017 are presented below:

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2016		12,743,877		$	26.41
Granted		7,867,683		$	34.73
Exercised		(1,442,411	)	$	18.49
Cancelled/forfeited		(1,225,713	)	$	30.48
Outstanding at December 31, 2017		17,943,436		$	30.42		8.1	$	55,794
Vested and expected to vest at December 31, 2017		17,943,436		$	30.42		8.1	$	55,794
Exercisable at December 31, 2017		6,464,292		$	26.07		6.6	$	41,449

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of Domestic and Foreign Pre-tax Income (Loss)

Domestic and foreign pre-tax income (loss) is as follows (in thousands):

	Years Ended December 31,
	2017			2016			2015
Domestic		(45,249	)	$	(18,419	)	$	25,854
Foreign		(243,035	)		(251,633	)		(189,967	)
		(288,284	)	$	(270,052	)	$	(164,113	)

Components of Deferred Tax Assets

The components of the deferred tax assets are as follows (in thousands):

	December 31,
	2017			2016
NOL carryforwards	$	163,059		$	168,753
R&D credit carryforwards		27,862			21,016
Capitalized R&D		5,606			3,977
Stock-based compensation		30,986			27,576
Other		10,110			6,102
		237,623			227,424
Valuation allowance		(237,623	)		(227,424	)
	$	—		$	—

Reconciliation of Income Taxes to Amount Computed by Applying Statutory Federal Income Tax Rate to Pretax Loss

A reconciliation of income taxes to the amount computed by applying the statutory federal income tax rate to the pretax loss is summarized as follows (in thousands):

	Years Ended December 31,
	2017			2016			2015
Amounts computed at statutory federal rate	$	(98,016	)	$	(91,818	)	$	(55,799	)
Stock-based compensation and other permanent differences		1,341			3,065			1,752
R&D credits		(5,573	)		(3,390	)		(3,782	)
Change in valuation allowance		(28,230	)		27,583			4,580
State taxes		(26	)		272			742
Contingencies		360			361			2,247
Foreign rate differential		61,480			64,065			48,456
Tax Cuts and Jobs Act		68,889			—			—
Other		894			1,203			2,134
Income tax expense	$	1,119		$	1,341		$	330

Unrecognized Tax Benefits

The following table provides a reconciliation of changes in unrecognized tax benefits (in thousands):

	Years Ended December 31,
	2017			2016		2015
Balance at beginning of period	$	2,664		$	2,301	$	—
Additions related to current period tax positions		361			363		2,301
Provisional impact of Tax Cuts and Jobs Act		(1,092	)		—		—
Balance at end of period	$	1,933		$	2,664	$	2,301

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Estimated Annual Future Minimum Payments under Operating Leases

Estimated annual future minimum payments related to the Company’s operating leases were as follows at December 31, 2017 (in thousands):

2018	$	2,529
2019		1,019
2020		320
2021		—
2022		—
Thereafter		—
	$	3,868

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data

	Fiscal Year 2017 Quarters
	1st			2nd			3rd			4th			Total
Revenues⁽¹⁾	$	15,286		$	30,475		$	35,578		$	43,562		$	124,901
Gross profit⁽²⁾	$	13,023		$	28,251		$	33,443		$	41,107		$	115,824
Net loss	$	(87,843	)	$	(67,441	)	$	(65,248	)	$	(68,871	)	$	(289,403	)
Basic and diluted net loss per share⁽³⁾	$	(0.72	)	$	(0.55	)	$	(0.53	)	$	(0.55	)	$	(2.36	)

	Fiscal Year 2016 Quarters
	1st			2nd			3rd			4th			Total
Revenues⁽¹⁾	$	4		$	97		$	5,268		$	11,962		$	17,331
Gross profit⁽²⁾	$	—		$	(429	)	$	4,423		$	10,258		$	14,252
Net loss	$	(49,762	)	$	(71,322	)	$	(71,613	)	$	(78,696	)	$	(271,393	)
Basic and diluted net loss per share⁽³⁾	$	(0.45	)	$	(0.63	)	$	(0.61	)	$	(0.65	)	$	(2.34	)

⁽¹⁾	The Company commenced commercial sales of NUPLAZID in May 2016. The quarters after March 31, 2016 reflect net product revenue related to NUPLAZID.

⁽²⁾	Determined by subtracting cost of product sales from product sales, net.

⁽³⁾	Net loss per common share, basic and diluted, are computed independently for each quarter and the full year based upon respective average shares outstanding. Therefore, the sum of the quarterly net loss per common share amounts may not equal the annual amounts reported.

Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Apr. 30, 2016 USD ($)	Dec. 31, 2017 USD ($) Customer Segment shares	Dec. 31, 2016 USD ($) Customer shares	Dec. 31, 2015 USD ($) shares	Mar. 31, 2017 USD ($)
Summary Of Significant Accounting Policy [Line Items]
Accounts receivable written off		$ 0	$ 0	$ 0
Charge on finished goods inventory		700,000	0	0
Impairment losses		0
One-time contingent regulatory milestone payment pursuant to agreement with Ipsen Group	$ 8,000,000
Finite-lived intangible assets, net	$ 8,000,000
Amortization of intangible assets		1,477,000	985,000	0
Estimated future amortization expense, 2018		1,500,000
Estimated future amortization expense, 2019		1,500,000
Estimated future amortization expense, 2020		1,500,000
Estimated future amortization expense, 2021		1,000,000
Advertising costs		15,600,000	1,600,000
Advertising costs capitalized as prepaid expenses		$ 0	$ 0
Number of large customers \| Customer		4	4
Stock compensation expense related to non-employee stock options		$ 75,532,000	$ 55,265,000	$ 40,194,000
Antidilutive securities to purchase common stock \| shares		18,526,000	14,739,000	11,525,000
Number of business segments \| Segment		1
ASU 2016-09
Summary Of Significant Accounting Policy [Line Items]
Increase in deferred tax assets to record unrecognized excess tax benefits					$ 36,800,000
Increase to additional paid-in capital with corresponding increase to accumulated deficit					300,000
Increase in deferred tax assets to record excess tax benefit					$ 100,000
Chief Executive Officer [Member]
Summary Of Significant Accounting Policy [Line Items]
Stock compensation expense related to non-employee stock options				$ 9,000,000
Customer Concentration Risk \| Sales Revenue, Product Line \| Four Customers
Summary Of Significant Accounting Policy [Line Items]
Concentration risk, percentage		89.00%	93.00%
Customer Concentration Risk \| Accounts Receivable \| Four Customers
Summary Of Significant Accounting Policy [Line Items]
Concentration risk, percentage		87.00%	91.00%

Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives by Major Asset Category (Detail)	12 Months Ended
	Dec. 31, 2017
Machinery and Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	5 years
Machinery and Equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	7 years
Computers and Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	10 years

Summary of Significant Accounting Policies - Weighted-Average Assumptions Used to Estimate Fair Value of Employee Stock Options (Detail) - Stock Options	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assumptions used to Determine Fair Value Options [Line Items]
Expected volatility	68.00%	78.00%	89.00%
Risk-free interest rate	2.00%
Risk-free interest rate, minimum		1.00%	1.00%
Risk-free interest rate, maximum		2.00%	2.00%
Expected dividend yield	0.00%	0.00%	0.00%
Expected life of options in years	5 years 9 months 18 days	5 years 8 months 12 days	5 years 8 months 12 days

Summary of Significant Accounting Policies - Weighted-Average Assumptions Used to Estimate Fair Value of Employee Stock Purchase Plan Rights (Detail) - Employee Stock Purchase Plan	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Stock Purchase Plan [Line Items]
Expected volatility, minimum	44.00%	60.00%	51.00%
Expected volatility, maximum	62.00%	77.00%	59.00%
Risk-free interest rate, minimum	1.00%	0.40%	0.10%
Risk-free interest rate, maximum	1.70%	1.00%	0.90%
Expected dividend yield	0.00%	0.00%	0.00%
Minimum
Employee Stock Purchase Plan [Line Items]
Expected life in years	6 months	6 months	6 months
Maximum
Employee Stock Purchase Plan [Line Items]
Expected life in years	2 years	2 years	2 years

Summary of Significant Accounting Policies - Summary of Stock-based Compensation Expense Included in Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 75,532	$ 55,265	$ 40,194
Cost of product sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	3,690	1,218
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	26,485	18,050	12,171
Sales, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 45,357	$ 35,997	$ 28,023

Investment Securities - Schedule of Investment Securities Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 272,331	$ 365,324
Unrealized Gains	1	172
Unrealized Losses	(408)	(80)
Estimated Fair Value	271,924	365,416
U.S. Treasury notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,976	82,484
Unrealized Gains		6
Unrealized Losses	(12)	(3)
Estimated Fair Value	32,964	82,487
Government sponsored enterprise securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,082	73,789
Unrealized Gains		1
Unrealized Losses	(10)	(5)
Estimated Fair Value	10,072	73,785
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	138,650	79,190
Unrealized Gains	1
Unrealized Losses	(321)	(72)
Estimated Fair Value	138,330	79,118
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	90,623	129,861
Unrealized Gains		165
Unrealized Losses	(65)
Estimated Fair Value	$ 90,558	$ 130,026

Investment Securities - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Available-for-sale, investment securities held with maturity dates more than one year and less than two years	$ 48,700,000	$ 0

Fair Value Measurements - Fair Value Measurements of Cash Equivalents and Available-For-Sale Investment Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 333,541	$ 523,433
Money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	38,057	129,292
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	71,021	211,779
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	38,057	129,292
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	262,520	311,654
U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	32,964	82,487
U.S. Treasury notes \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	32,964	82,487
Government sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	10,072	88,773
Government sponsored enterprise securities \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	10,072	88,773
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	154,396	82,857
Corporate debt securities \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	154,396	82,857
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	98,052	140,024
Commercial paper \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 98,052	$ 140,024

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References + Details

Balance Sheet Details - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished goods	$ 1,164	$ 2,355
Raw material	4,084	1,820
Inventory	$ 5,248	$ 4,175

Balance Sheet Details - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 6,891	$ 6,489
Accumulated depreciation	(4,229)	(3,408)
Property and equipment, net	2,662	3,081
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,076	1,087
Computers and Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,868	2,718
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,642	1,317
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,305	1,141
Construction-in-Process
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 226

Balance Sheet Details - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Depreciation of property and equipment	$ 1,236	$ 843	$ 647
Removal of fully depreciated property, machinery and equipment	$ 400	$ 200	$ 100

Balance Sheet Details - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued compensation and benefits	$ 15,260	$ 14,382
Accrued consulting and professional fees	9,395	9,488
Accrued research and development services	9,487	8,551
Accrued sales allowances	3,591	1,999
Other	2,511	1,609
Accrued liabilities	$ 40,244	$ 36,029

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended								12 Months Ended
	Jun. 30, 2017	Aug. 31, 2016	Jun. 30, 2016	Apr. 30, 2016	Jan. 31, 2016	Jun. 30, 2015	Dec. 31, 2012	Jan. 31, 2011	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Class of Stock [Line Items]
Net proceeds from sale of common stock		$ 215,900,000			$ 281,600,000				$ 31,188,000	$ 518,896,000	$ 14,547,000
Share of common stock issued		6,969,696			10,344,827		19,000,000	12,565,446
Common stock, par value									$ 0.0001	$ 0.0001
Value of shares purchased by Baker Entities in public offerings									$ 12,000	$ 12,000
Proceed from sale of stock and warrants							$ 80,500,000	$ 13,900,000
Common stock sale price per share							$ 4.43	$ 1.19375
Warrants exercised for purchase of common shares									1,465,968			1,759,162	1,172,774
Issuance of common stock from exercise of warrants on a net issuance basis (in shares)									1,408,570			1,643,006	874,719
Closing market price of Common stock									$ 30.11
Aggregate intrinsic value of stock options exercised									$ 24,400,000	$ 43,200,000	$ 55,900,000
Cash received from options exercised									$ 26,700,000
Weighted average per share fair value of options granted									$ 21.11	$ 17.65	$ 25.80
Unrecognized compensation costs									$ 206,500,000
Weighted average period cost expected to be recognized									3 years 2 months 8 days
Issuance of common stock pursuant to employee stock purchase plan									$ 4,522,000	$ 3,131,000	$ 1,556,000
Payment received from stockholder pursuant to a settlement agreement related to short-swing profits				$ 14,300,000						$ 14,320,000
Prior stockholders percentage of equity holding				10.00%
Stock Options \| Equity Incentive Plan 2010
Class of Stock [Line Items]
Exercise price of Options as percentage of fair market value														100.00%
Options maximum expiration term														10 years
Options vesting period														4 years
Number of common stock authorized for issuance									25,997,247
Common stock available for grants									8,053,811
Common stock reserved for issuance under stock purchase plan	5,500,000		3,000,000			5,000,000
Stock Options \| Equity Incentive Plan 2004
Class of Stock [Line Items]
Exercise price of Options as percentage of fair market value									100.00%
Options vesting period									4 years
Number of periods additional number of shares could be added to shares authorized for issuance									10 years
Employee Stock Purchase Plan
Class of Stock [Line Items]
Number of common stock authorized for issuance									1,925,000
Common stock reserved for issuance under stock purchase plan			400,000
Term of ESPP Evergreen Provision									10 years
Common stock remained available for issuance pursuant to the Purchase Plan									388,011
Eligible employees percentage of earnings withheld to purchase shares under purchase plan									15.00%
Purchase price of common stock as percentage of market value									85.00%
Issuance of common stock pursuant to employee stock purchase plan									192,402	136,283	68,793
Average per share price of stock issued under purchase plan									$ 23.50	$ 22.97	$ 22.62
Weighted average per share fair value of purchase rights granted									$ 11.44	$ 12.34	$ 14.31
Issuance of common stock pursuant to employee stock purchase plan									$ 4,500,000	$ 3,100,000	$ 1,600,000
Expire on December 17, 2019
Class of Stock [Line Items]
Warrants issued							500,000						500,000
Warrants issuance price per share							$ 4.42
Warrant exercise price							$ 0.01						$ 0.01
Warrant expiration date									Dec. 17, 2019
Issuance of warrant value							$ 2,200,000
Warrant risk free interest rate							1.10%
volatility percentage							105.80%
Warrant term							7 years
Warrants outstanding									500,000
Description of warrant									Per their terms, the warrants to purchase 500,000 shares of common stock, all of which remained outstanding at December 31, 2017, may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99 percent following such exercise.
Dividend yield							0.00%
Expired on January 11, 2018
Class of Stock [Line Items]
Warrant exercise price								$ 1.38
Warrant expiration date									Jan. 11, 2018
Issuance of warrant value								$ 3,300,000
Warrant risk free interest rate								2.80%
volatility percentage								99.00%
Warrant term								7 years
Number of common stock per unit sold								1
Dividend yield								0.00%
Number of common stock allowed to purchase								0.35
Warrants outstanding to purchase common stock									0
Registration Rights Agreement
Class of Stock [Line Items]
Common stock, par value					$ 0.0001
Expiration period					10 years
Maximum amount of expense agreed to bear under the agreement					$ 50,000
Registration Rights Agreement \| Baker Brothers Life Sciences L.P.
Class of Stock [Line Items]
Value of shares purchased by Baker Entities in public offerings		$ 43,000,000			$ 75,000,000
Option To Purchase Additional Shares
Class of Stock [Line Items]
Share of common stock issued		909,090

Stock Option Transactions (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Number of Shares
Options Outstanding, Beginning Balance \| shares	12,743,877
Granted \| shares	7,867,683
Exercised \| shares	(1,442,411)
Cancelled/forfeited \| shares	(1,225,713)
Options Outstanding, Ending Balance \| shares	17,943,436
Vested and expected to vest \| shares	17,943,436
Exercisable \| shares	6,464,292
Weighted Average Exercise Prices
Weighted Average Exercise Prices, Beginning Balance \| $ / shares	$ 26.41
Weighted Average Exercise Prices, granted \| $ / shares	34.73
Weighted Average Exercise Prices, exercised \| $ / shares	18.49
Weighted Average Exercise Prices, Cancelled/forfeited \| $ / shares	30.48
Weighted Average Exercise Prices, Ending Balance \| $ / shares	30.42
Weighted Average Exercise Prices, Vested and expected to vest \| $ / shares	30.42
Weighted Average Exercise Prices, Exercisable \| $ / shares	$ 26.07
Weighted average remaining contractual term, Outstanding	8 years 1 month 7 days
Weighted average remaining contractual term, Vested and expected to vest	8 years 1 month 7 days
Weighted average remaining contractual term, Exercisable	6 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding \| $	$ 55,794
Aggregate Intrinsic Value, Vested and expected to vest \| $	55,794
Aggregate Intrinsic Value, Exercisable \| $	$ 41,449

401 (k) Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Maximum contribution by employee, percentage of pretax earnings	60.00%
Percentage of company's matching contribution with respect to each participant's contribution	100.00%
Company matching contributions to maximum employees eligible compensation	5.00%
Company contributions to 401 (k) plan	$ 3.3	$ 2.1	$ 1.0

Income Taxes - Summary of Domestic and Foreign Pre-tax Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
Domestic pre-tax income (loss)	$ (45,249)	$ (18,419)	$ 25,854
Foreign pre-tax income (loss)	(243,035)	(251,633)	(189,967)
Total pre-tax income (loss)	$ (288,284)	$ (270,052)	$ (164,113)

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Line Items]
State income tax provision		$ 1,100,000	$ 1,300,000	$ 300,000
Federal R&D credit carryforwards		19,800,000
Increase in valuation allowance of deferred tax assets		10,200,000
Deferred tax benefit or expense related to remeasurement of deferred tax assets and liabilities		0
Unrecognized tax reserves recorded during period		361,000	363,000	2,301,000
Interest and/or penalties accrued		0	0
Tax cuts and jobs act provisional adjustment		1,092,000
Interest and/or penalties		0	$ 0	$ 0
Scenario Forecast
Income Tax [Line Items]
Tax rate	21.00%
Remeasurement of deferred tax balance	$ 68,900,000
Federal
Income Tax [Line Items]
Operating loss carryforwards		$ 407,100,000
Remaining net operating loss carryforward, expiration year		2023
Federal \| Expiring in 2018
Income Tax [Line Items]
Operating loss carryforwards		$ 2,300,000
State
Income Tax [Line Items]
Operating loss carryforwards		$ 340,000,000
Remaining net operating loss carryforward, expiration year		2023
Research and development credit carryforwards with no expiration date		$ 10,000,000
State \| Expiring in 2018 \| Maximum
Income Tax [Line Items]
Operating loss carryforwards		100,000
State \| Expiring in 2023
Income Tax [Line Items]
Net operating loss carryforwards with no expiration date		200,000
Foreign
Income Tax [Line Items]
Operating loss carryforwards		647,400,000
Net operating loss carryforwards with no expiration date		3,600,000
Foreign \| Operating Loss Carryforwards Expiring 2022
Income Tax [Line Items]
Operating loss carryforwards		643,900,000
Expire in 2018
Income Tax [Line Items]
Federal R&D credit carryforwards		$ 100,000

Income Taxes - Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
NOL carryforwards	$ 163,059	$ 168,753
R&D credit carryforwards	27,862	21,016
Capitalized R&D	5,606	3,977
Stock-based compensation	30,986	27,576
Other	10,110	6,102
Deferred Tax Assets, Gross	237,623	227,424
Valuation allowance	(237,623)	(227,424)
Deferred Tax Assets, Net	$ 0	$ 0

Income Taxes - Reconciliation of Income Taxes to Amount Computed by Applying Statutory Federal Income Tax Rate to Pretax Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Amounts computed at statutory federal rate	$ (98,016)	$ (91,818)	$ (55,799)
Stock-based compensation and other permanent differences	1,341	3,065	1,752
R&D credits	(5,573)	(3,390)	(3,782)
Change in valuation allowance	(28,230)	27,583	4,580
State taxes	(26)	272	742
Contingencies	360	361	2,247
Foreign rate differential	61,480	64,065	48,456
Tax Cuts and Jobs Act	68,889
Other	894	1,203	2,134
Income tax expense	$ 1,119	$ 1,341	$ 330

Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 2,664	$ 2,301
Additions related to current period tax positions	361	363	$ 2,301
Provisional impact of Tax Cuts and Jobs Act	(1,092)
Balance at end of period	$ 1,933	$ 2,664	$ 2,301

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Commitments [Line Items]
Operating lease, expiration year	2020-05
Rent expense	$ 3,800,000	$ 2,800,000	$ 2,900,000
Restricted cash	$ 2,475,000	2,375,000
Maximum
Other Commitments [Line Items]
Percentage of royalty payments obligation on net product sales	2.00%
Letter of Credit [Member]
Other Commitments [Line Items]
Restricted cash			$ 500,000
Letter of Credit [Member] \| Corporate Credit Card Program
Other Commitments [Line Items]
Restricted cash		$ 2,000,000
Vehicles [Member]
Other Commitments [Line Items]
Operating leases arrangement term			36 months

Commitments and Contingencies - Estimated Annual Future Minimum Payments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018	$ 2,529
2019	1,019
2020	320
2021	0
2022	0
Thereafter	0
Operating Leases, Future Minimum Payments Due, Total	$ 3,868

Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Detail) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Revenues

$ 43,562

^[1]

$ 35,578

^[1]

$ 30,475

^[1]

$ 15,286

^[1]

$ 11,962

^[1]

$ 5,268

^[1]

$ 97

^[1]

$ 4

^[1]

$ 124,901

^[1]

$ 17,331

^[1]

$ 61

Gross profit

^[2]

41,107

33,443

28,251

13,023

10,258

4,423

(429)

115,824

14,252

Net loss

$ (68,871)

$ (65,248)

$ (67,441)

$ (87,843)

$ (78,696)

$ (71,613)

$ (71,322)

$ (49,762)

$ (289,403)

$ (271,393)

$ (164,443)

Basic and diluted net loss per share

$ (0.55)

^[3]

$ (0.53)

^[3]

$ (0.55)

^[3]

$ (0.72)

^[3]

$ (0.65)

^[3]

$ (0.61)

^[3]

$ (0.63)

^[3]

$ (0.45)

^[3]

$ (2.36)

^[3]

$ (2.34)

^[3]

$ (1.63)

[1]	The Company commenced commercial sales of NUPLAZID in May 2016. The quarters after March 31, 2016 reflect net product revenue related to NUPLAZID.
[2]	Determined by subtracting cost of product sales from product sales, net.
[3]	Net loss per common share, basic and diluted, are computed independently for each quarter and the full year based upon respective average shares outstanding. Therefore, the sum of the quarterly net loss per common share amounts may not equal the annual amounts reported.

SCHEDULE II - Valuation and Qualifying Accounts (Detail) - Allowance for Distribution Fees, Discounts and Chargebacks - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 201
Additions, Provision Related to Current Period Sales	12,837	$ 2,163
Deductions, Actual Distribution Fees, Discounts and Chargebacks Related to Current Period Sales	(12,591)	(1,962)
Deductions, Actual Distribution Fees, Discounts and Chargebacks Related to Prior Period Sales	(201)
Balance at End of Period	$ 246	$ 201