ACADIA Pharmaceuticals (ACAD) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	ACAD
Entity Registrant Name	ACADIA PHARMACEUTICALS INC
Entity Central Index Key	1,070,494
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		125,074,557

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 63,897	$ 69,418
Investment securities, available-for-sale	150,239	271,924
Accounts receivable, net	19,958	17,343
Interest and other receivables	724	1,087
Inventory	4,347	5,248
Prepaid expenses	14,951	8,457
Total current assets	254,116	373,477
Property and equipment, net	3,372	2,662
Intangible assets, net	4,431	5,538
Restricted cash	3,111	2,475
Other assets	1,426	354
Total assets	266,456	384,506
Liabilities and stockholders’ equity
Accounts payable	2,955	8,786
Accrued liabilities	38,852	40,244
Total current liabilities	41,807	49,030
Long-term liabilities	1,209	191
Total liabilities	43,016	49,221
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized at September 30, 2018 and December 31, 2017; no shares issued and outstanding at September 30, 2018 and December 31, 2017
Common stock, $0.0001 par value; 225,000,000 shares authorized at September 30, 2018 and December 31, 2017; 125,023,015 shares and 124,410,552 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	12	12
Additional paid-in capital	1,627,113	1,559,343
Accumulated deficit	(1,403,371)	(1,223,671)
Accumulated other comprehensive loss	(314)	(399)
Total stockholders’ equity	223,440	335,285
Total liabilities and stockholders’ equity	$ 266,456	$ 384,506

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
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	125,023,015	124,410,552
Common stock, shares outstanding	125,023,015	124,410,552

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Total revenues	$ 58,305	$ 35,578	$ 164,236	$ 81,339
Operating expenses
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of product sales	$ 3,839	$ 2,135	$ 9,554	$ 6,622
License fees and royalties	1,536	1,078	4,384	2,735
Research and development	53,112	36,421	138,980	106,010
Selling, general and administrative	61,089	61,588	191,487	188,373
Total operating expenses	119,576	101,222	344,405	303,740
Loss from operations	(61,271)	(65,644)	(180,169)	(222,401)
Interest income, net	1,229	1,063	3,678	3,019
Other expense	(1,720)		(1,967)
Loss before income taxes	(61,762)	(64,581)	(178,458)	(219,382)
Income tax expense	376	667	1,242	1,150
Net loss	$ (62,138)	$ (65,248)	$ (179,700)	$ (220,532)
Net loss per common share, basic and diluted	$ (0.50)	$ (0.53)	$ (1.44)	$ (1.81)
Weighted average common shares outstanding, basic and diluted	125,009	122,484	124,883	122,089

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (62,138)	$ (65,248)	$ (179,700)	$ (220,532)
Other comprehensive gain (loss):
Unrealized gain (loss) on investment securities	186	25	83	(174)
Foreign currency translation adjustments		(1)	2	(5)
Comprehensive loss	$ (61,952)	$ (65,224)	$ (179,615)	$ (220,711)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net loss	$ (179,700)	$ (220,532)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	61,163	53,513
Amortization of premiums and accretion of discounts on investment securities, net	(415)	(138)
Amortization of intangible assets	1,107	1,108
Loss on strategic investments	1,967
Depreciation	1,116	904
Loss on disposal of assets	27
Changes in operating assets and liabilities:
Accounts receivable, net	(2,615)	(8,318)
Interest and other receivables	363	204
Inventory	1,464	(1,645)
Prepaid expenses	(6,494)	(7,011)
Other assets	111	416
Accounts payable	(5,856)	(950)
Accrued liabilities	(1,647)	(2,857)
Deferred revenue		(2,644)
Long-term liabilities	1,018	88
Net cash used in operating activities	(128,391)	(187,862)
Cash flows from investing activities
Purchases of investment securities	(95,379)	(353,840)
Maturities of investment securities	217,562	465,211
Proceeds from sale of property and equipment	5
Purchases of strategic investments	(3,150)
Purchases of property and equipment	(1,578)	(805)
Net cash provided by investing activities	117,460	110,566
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	6,044	26,397
Net cash provided by financing activities	6,044	26,397
Effect of exchange rate changes on cash	2	(5)
Net decrease in cash, cash equivalents and restricted cash	(4,885)	(50,904)
Cash, cash equivalents and restricted cash
Beginning of period	71,893	165,995
End of period	67,008	115,091
Supplemental disclosure of noncash information:
Property and equipment purchases in accounts payable and accrued liabilities	280	9
Stock-based compensation capitalized in inventory	$ (563)	$ 284

Organization and Business

Organization and Business	9 Months Ended
	Sep. 30, 2018
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. In April 2016, the U.S. Food and Drug Administration (“FDA”) approved the Company’s first drug, NUPLAZID ®

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company should be read in conjunction with the audited financial statements and notes thereto as of and for the year ended December 31, 2017 included in the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (the “SEC”). The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, since they are interim statements, the accompanying financial statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the accompanying financial statements reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates . Reclassifications The Company has reclassified certain prior period amounts to conform to current period presentation. Specifically, it has reclassified income tax expense previously included within selling, general and administrative expense and presented it separately in the Condensed Consolidated Statements of Operations. This reclassification reduced the Company’s previously stated selling, general and administrative expense and total operating expense for the three and nine months ended September 30, 2017 by $0.7 million and $1.2 million, respectively. The reclassification had no impact on the Company’s net loss or stockholders’ equity as previously reported. In addition, pursuant to the adoption of ASU 2016-18, Statement of Cash Flows: Restricted Cash beginning-of-period and end-of-period total amounts Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 Beginning of period End of period Beginning of period End of period Cash and cash equivalents $ 69,418 $ 63,897 $ 163,620 $ 112,616 Restricted cash 2,475 3,111 2,375 2,475 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 71,893 $ 67,008 $ 165,995 $ 115,091 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 September 30, 2018, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented. 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 $0.4 million and $1.1 million for each of the three and nine months ended September 30, 2018 and 2017, respectively. As of September 30, 2018, estimated future amortization expense related to the Company’s intangible asset was $0.4 million for the remainder of 2018, $1.5 million for each of 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. Revenue Recognition Product Sales, Net The Company’s net product sales consist of U.S. sales of NUPLAZID. Effective January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), and applied all the related amendments to all of the contracts using the modified-retrospective method. While results for reporting periods beginning after January 1, 2018 are presented under the new guidance, prior period amounts are not adjusted and continue to be reported under the accounting standards in effect for the prior period. The accounting policy for revenue recognition for periods prior to January 1, 2018 is described in Note 2 of the Notes to the Consolidated Financial Statements included in the Company’s Annual Report. No cumulative effect adjustment to the opening balance of retained earnings was necessary upon adoption, and there is no reconciliation of the Company’s Condensed Consolidated Statements of Operations, as no revenue recognition differences were identified when comparing the revenue recognition criteria under Topic 606 to previous requirements. Product shipping and handling costs are included in cost of product sales. The Company recognizes revenue from product sales at the net sales price (the “transaction price”) which includes estimates of variable consideration for which reserves are established and reflects each of these as either a reduction to the related account receivable or as an accrued liability, depending on how the amount payable is settled. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which the Company is entitled based on the terms of the contract. The amount of variable consideration that is included in the transaction price may be constrained, and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from estimates, the Company may need to adjust its estimates, which would affect net revenue in the period of adjustment. 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. 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. 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 for product returns, the Company also considers historical product returns, the underlying product demand, and industry data specific to the specialty pharmaceutical distribution industry.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	3. 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 plan 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 anti-dilutive. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	4. Stock-Based Compensation The following table summarizes the total stock-based compensation expense included in the Company’s Condensed Consolidated Statements of Operations for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of product sales $ 838 $ 1,210 $ 3,025 $ 2,971 Research and development 8,066 6,877 23,617 18,598 Selling, general and administrative 11,265 11,611 34,521 31,944 $ 20,169 $ 19,698 $ 61,163 $ 53,513

Balance Sheet Details

Balance Sheet Details	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Details	5. Balance Sheet Details Inventory consisted of the following (in thousands): September 30, 2018 December 31, 2017 Raw material $ 3,005 $ 4,084 Finished goods 897 1,164 Work in process 445 — $ 4,347 $ 5,248 Accrued liabilities consisted of the following (in thousands): September 30, 2018 December 31, 2017 Accrued compensation and benefits $ 14,467 $ 15,260 Accrued consulting and professional fees 9,003 9,395 Accrued research and development services 8,978 9,487 Accrued sales allowances 3,485 3,591 Other 2,919 2,511 $ 38,852 $ 40,244

Investments

Investments	9 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Investments	6. Investments The carrying value and amortized cost of the Company’s investments, summarized by major security type, consisted of the following (in thousands): September 30, 2018 Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities $ 124,521 $ 5 $ (318 ) $ 124,208 Commercial paper 26,042 1 (12 ) 26,031 Equity securities 3,149 — (1,967 ) 1,182 $ 153,712 $ 6 $ (2,297 ) $ 151,421 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 The Company has classified all of its available-for-sale investment securities, including those with maturities beyond one year, as current assets on its Condensed 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 September 30, 2018 and December 31, 2017, the Company held $35.1 million and $48.7 million, respectively, of available-for-sale investment securities with contractual maturity dates of more than one year and less than two years. The Company has classified all equity securities as other assets on its Condensed Consolidated Balance Sheets. At September 30, 2018 the Company had 37 securities in an unrealized loss position and at December 31, 2017 the Company had 54 securities in an unrealized loss position. The following table presents gross unrealized losses and fair value for those available-for-sale investments that were in an unrealized loss position as of September 30, 2018 and December 31, 2017, aggregated by investment category and length of time that individual securities have been in a continuous loss position (in thousands): Less Than 12 Months 12 Months or Greater Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses September 30, 2018: Corporate debt securities $ 81,064 $ (189 ) $ 28,249 $ (128 ) $ 109,313 $ (317 ) Commercial paper 15,546 (12 ) 2,998 (1 ) 18,544 (13 ) Total $ 96,610 $ (201 ) $ 31,247 $ (129 ) $ 127,857 $ (330 ) December 31, 2017: U.S. Treasury notes $ 32,964 $ (12 ) $ — $ — $ 32,964 $ (12 ) Government sponsored enterprise securities 10,072 (10 ) — — 10,072 (10 ) Corporate debt securities 129,820 (321 ) — — 129,820 (321 ) Commercial paper 90,558 (65 ) — — 90,558 (65 ) Total $ 263,414 $ (408 ) $ — $ — $ 263,414 $ (408 ) 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 September 30, 2018 and December 31, 2017.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. Fair Value Measurements The Company’s investments include cash equivalents, available-for-sale investment securities consisting of money market funds, U.S. Treasury notes, and high quality, marketable debt instruments of corporations and government sponsored enterprises in accordance with the Company’s investment policy and equity investments. The Company’s investment policy defines allowable investment debt securities and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. All investment debt 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, available-for-sale investment securities and equity securities are classified within the fair value hierarchy as defined by authoritative guidance. The Company’s investment debt securities and equity 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 September 30, 2018 and December 31, 2017. 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 of the Company’s cash equivalents, available-for-sale investment securities and equity securities at September 30, 2018 and December 31, 2017 consisted of the following (in thousands): Fair Value Measurements at Reporting Date Using September 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 55,160 $ 55,160 $ — $ — Equity securities 1,182 1,182 — — Corporate debt securities 124,208 — 124,208 — Commercial paper 26,031 — 26,031 — $ 206,581 $ 56,342 $ 150,239 $ — 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 $ —

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	8. 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 then 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 September 30, 2018, may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99 percent following such exercise.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Leases and Other Long-Term Commitments In May 2018, the Company entered into a lease agreement to lease facilities under a noncancelable operating lease that expires January 2026. Estimated annual future minimum payments related to the Company’s operating leases were as follows at September 30, 2018 (in thousands): 2018 $ 748 2019 1,880 2020 1,192 2021 886 2022 898 Thereafter 2,848 $ 8,452 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 for $2.0 million, which has automatic annual extensions and is fully secured by restricted cash. Fleet Program In connection with the Company’s fleet program, the Company established letters of credit with the leasing entities totaling $0.7 million, which have automatic annual extensions and are fully secured by restricted cash. Legal Proceedings Between July 19 and August 3, 2018, following recent negative publicity about NUPLAZID, three purported Company stockholders filed putative securities class action complaints (captioned Staublein v. ACADIA Pharmaceuticals, Inc., Case No. 18-cv-01647-JAH-MDD, Stone v. ACADIA Pharmaceuticals Inc., Case No. 18-cv-01672-LAB-JMA, and Barglow v. ACADIA Pharmaceuticals Inc., Case No. 18-cv-1812-DMS-WVG) in the U.S. District Court for the Southern District of California against the Company and certain of its current executive officers. The complaints generally allege that defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 by making materially false and misleading statements regarding the Company’s business, operations, and prospects by failing to disclose that adverse events and safety concerns regarding NUPLAZID threatened initial and continuing FDA approval, and by failing to disclose that the Company engaged in business practices likely to attract regulatory scrutiny. The complaints seek unspecified monetary damages and other relief. Several putative lead plaintiffs have filed motions to consolidate the cases and to appoint a lead plaintiff. The motions have been fully briefed and are set to be heard on January 3, 2019. The defendants’ response to the complaints is stayed pending resolution of the lead plaintiff motions. The Company has assessed such legal proceedings, and given the unpredictability inherent in litigation, the Company cannot predict the outcome of these matters. At this time, the Company is unable to estimate possible losses or ranges of losses that may result from such legal proceedings, and it has not accrued any amounts in connection with such legal proceedings other than ongoing attorneys’ fees Government Investigation In September 2018 the Company received a civil investigative demand (“CID”) from the Department of Justice (“DOJ”)

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2018
License Agreements [Abstract]
License Agreements	10. License Agreements In May 2018, the Company signed an Exclusivity Deed (the “Deed”) with Neuren Pharmaceuticals Limited (“Neuren”) that provided for exclusive negotiations for a period of three months from the date of the Deed. Under the terms of the Deed, the Company invested $3.1 million to subscribe for 1,330,000 shares of the company and paid $0.9 million for the exclusive right to negotiate a deal with Neuren, which was recorded in selling, general and administrative expenses in the Condensed Consolidated Statements of Operations for the nine months ended September 30, 2018. At September 30, 2018, the Company continues to hold the equity securities as a strategic investment in which the Company does not have a controlling interest or significant influence. Publicly held equity securities are measured using quoted prices in their respective active markets with changes recorded through other expense on the statements of operations. Net loss on strategic investments recognized in other expense in the Condensed Consolidated Statements of Operations in the three and nine months ended September 30, 2018 was $1.7 million and $2.0 million, respectively. As of September 30, 2018, the aggregate carrying amount of the Company’s strategic equity investment was $1.2 million included in other assets on the Condensed Consolidated Balance Sheets. In August 2018, the Company entered into a license agreement with Neuren and obtained exclusive North American rights to develop and commercialize trofinetide for Rett syndrome and other indications. Under the terms of the agreement, Neuren received an upfront payment of $10.0 million and is eligible to receive milestone payments of up to $455.0 million, based on the achievement of certain development and annual net sales milestones. In addition, Neuren is eligible to receive tiered, escalating, double-digit percentage royalties based on net sales . The license agreement was accounted for as an asset acquisition and the upfront cash payment of $10.0 million has been recorded

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Recent Accounting Pronouncements	11. Recent Accounting Pronouncements In December 2017, the U.S. Securities and Exchange Commission (“SEC”) staff issued SAB 118, which provides guidance on accounting for the tax effects of the Tax Cuts and Jobs Act (the “Act”). 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. In November 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-18, Statement of Cash Flows: Restricted Cash 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 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. In January 2018, the FASB issued ASU 2018-01, Leases: Land Easement Practical Expedient for Transition to Topic 842 , which facilitates the implementation of ASU 2016-02. ASU 2018-01 would give entities the option to apply ASU 2016-02 as of the effective date, rather than as of the beginning of the earliest period presented. Under this additional option transition method, a cumulative-effect adjustment would be recognized in the opening balance of retained earnings in the period of adoption. The effective date of the transition requirements for the amendment is the same as the effective date and transition requirements in ASU 2016-02. In order to adopt the new standard on January 1, 2019, the Company is currently designing changes to its processes, policies, and controls for lease accounting. The Company expects to elect the standard’s package of practical expedients on adoption, which allows the Company to carry forward its historical assessment of whether existing agreements contain a lease and the classification of the existing lease agreements. While the Company continues to review the existing lease agreements and assess the effects of adoption, it anticipates substantially all of its real-estate operating lease commitments will be recognized as lease liabilities with corresponding right-of-use assets upon adoption, resulting in a significant increase in the assets and liabilities recorded on its Condensed Consolidated Balance Sheets. 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 GAAP. On January 1, 2018, the Company adopted ASU 2014-09 and all the related guidance.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company should be read in conjunction with the audited financial statements and notes thereto as of and for the year ended December 31, 2017 included in the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (the “SEC”). The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, since they are interim statements, the accompanying financial statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the accompanying financial statements reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates .
Reclassifications	Reclassifications The Company has reclassified certain prior period amounts to conform to current period presentation. Specifically, it has reclassified income tax expense previously included within selling, general and administrative expense and presented it separately in the Condensed Consolidated Statements of Operations. This reclassification reduced the Company’s previously stated selling, general and administrative expense and total operating expense for the three and nine months ended September 30, 2017 by $0.7 million and $1.2 million, respectively. The reclassification had no impact on the Company’s net loss or stockholders’ equity as previously reported. In addition, pursuant to the adoption of ASU 2016-18, Statement of Cash Flows: Restricted Cash beginning-of-period and end-of-period total amounts Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 Beginning of period End of period Beginning of period End of period Cash and cash equivalents $ 69,418 $ 63,897 $ 163,620 $ 112,616 Restricted cash 2,475 3,111 2,375 2,475 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 71,893 $ 67,008 $ 165,995 $ 115,091
Accounts Receivable	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 September 30, 2018, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented.
License Fees and Royalties	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 $0.4 million and $1.1 million for each of the three and nine months ended September 30, 2018 and 2017, respectively. As of September 30, 2018, estimated future amortization expense related to the Company’s intangible asset was $0.4 million for the remainder of 2018, $1.5 million for each of 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.
Revenue Recognition	Revenue Recognition Product Sales, Net The Company’s net product sales consist of U.S. sales of NUPLAZID. Effective January 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), and applied all the related amendments to all of the contracts using the modified-retrospective method. While results for reporting periods beginning after January 1, 2018 are presented under the new guidance, prior period amounts are not adjusted and continue to be reported under the accounting standards in effect for the prior period. The accounting policy for revenue recognition for periods prior to January 1, 2018 is described in Note 2 of the Notes to the Consolidated Financial Statements included in the Company’s Annual Report. No cumulative effect adjustment to the opening balance of retained earnings was necessary upon adoption, and there is no reconciliation of the Company’s Condensed Consolidated Statements of Operations, as no revenue recognition differences were identified when comparing the revenue recognition criteria under Topic 606 to previous requirements. Product shipping and handling costs are included in cost of product sales. The Company recognizes revenue from product sales at the net sales price (the “transaction price”) which includes estimates of variable consideration for which reserves are established and reflects each of these as either a reduction to the related account receivable or as an accrued liability, depending on how the amount payable is settled. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which the Company is entitled based on the terms of the contract. The amount of variable consideration that is included in the transaction price may be constrained, and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from estimates, the Company may need to adjust its estimates, which would affect net revenue in the period of adjustment. 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. 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. 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 for product returns, the Company also considers historical product returns, the underlying product demand, and industry data specific to the specialty pharmaceutical distribution industry.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows (in thousands): Nine Months Ended September 30, 2018 Nine Months Ended September 30, 2017 Beginning of period End of period Beginning of period End of period Cash and cash equivalents $ 69,418 $ 63,897 $ 163,620 $ 112,616 Restricted cash 2,475 3,111 2,375 2,475 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 71,893 $ 67,008 $ 165,995 $ 115,091

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-based Compensation Expense Included in Condensed Consolidated Statements of Operations	The following table summarizes the total stock-based compensation expense included in the Company’s Condensed Consolidated Statements of Operations for the periods presented (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Cost of product sales $ 838 $ 1,210 $ 3,025 $ 2,971 Research and development 8,066 6,877 23,617 18,598 Selling, general and administrative 11,265 11,611 34,521 31,944 $ 20,169 $ 19,698 $ 61,163 $ 53,513

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Inventory	Inventory consisted of the following (in thousands): September 30, 2018 December 31, 2017 Raw material $ 3,005 $ 4,084 Finished goods 897 1,164 Work in process 445 — $ 4,347 $ 5,248
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): September 30, 2018 December 31, 2017 Accrued compensation and benefits $ 14,467 $ 15,260 Accrued consulting and professional fees 9,003 9,395 Accrued research and development services 8,978 9,487 Accrued sales allowances 3,485 3,591 Other 2,919 2,511 $ 38,852 $ 40,244

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Carrying Value and Amortized Cost of Company’s Investments Summarized by Major Security Type	The carrying value and amortized cost of the Company’s investments, summarized by major security type, consisted of the following (in thousands): September 30, 2018 Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value Corporate debt securities $ 124,521 $ 5 $ (318 ) $ 124,208 Commercial paper 26,042 1 (12 ) 26,031 Equity securities 3,149 — (1,967 ) 1,182 $ 153,712 $ 6 $ (2,297 ) $ 151,421 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
Summary of Gross Unrealized Losses and Fair Value of Available-For-Sale Investments in Unrealized Loss Position	The following table presents gross unrealized losses and fair value for those available-for-sale investments that were in an unrealized loss position as of September 30, 2018 and December 31, 2017, aggregated by investment category and length of time that individual securities have been in a continuous loss position (in thousands): Less Than 12 Months 12 Months or Greater Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses September 30, 2018: Corporate debt securities $ 81,064 $ (189 ) $ 28,249 $ (128 ) $ 109,313 $ (317 ) Commercial paper 15,546 (12 ) 2,998 (1 ) 18,544 (13 ) Total $ 96,610 $ (201 ) $ 31,247 $ (129 ) $ 127,857 $ (330 ) December 31, 2017: U.S. Treasury notes $ 32,964 $ (12 ) $ — $ — $ 32,964 $ (12 ) Government sponsored enterprise securities 10,072 (10 ) — — 10,072 (10 ) Corporate debt securities 129,820 (321 ) — — 129,820 (321 ) Commercial paper 90,558 (65 ) — — 90,558 (65 ) Total $ 263,414 $ (408 ) $ — $ — $ 263,414 $ (408 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Cash Equivalents, Available-For-Sale Investment Securities and Equity Securities	The recurring fair value of the Company’s cash equivalents, available-for-sale investment securities and equity securities at September 30, 2018 and December 31, 2017 consisted of the following (in thousands): Fair Value Measurements at Reporting Date Using September 30, 2018 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market fund $ 55,160 $ 55,160 $ — $ — Equity securities 1,182 1,182 — — Corporate debt securities 124,208 — 124,208 — Commercial paper 26,031 — 26,031 — $ 206,581 $ 56,342 $ 150,239 $ — 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 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
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 September 30, 2018 (in thousands): 2018 $ 748 2019 1,880 2020 1,192 2021 886 2022 898 Thereafter 2,848 $ 8,452

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net cash used in operations				$ (128,391,000)	$ (187,862,000)
Net decrease in cash and cash equivalents				(4,885,000)	(50,904,000)
Accounts receivable written off				0	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		$ 400,000	$ 400,000	1,107,000	1,108,000
Estimated future amortization expense, remainder of 2018		400,000		400,000
Estimated future amortization expense, 2019		1,500,000		1,500,000
Estimated future amortization expense, 2020		1,500,000		1,500,000
Estimated future amortization expense, 2021		1,000,000		1,000,000
Revenue recognition		(1,403,371,000)		(1,403,371,000)			$ (1,223,671,000)
ASU 2016-18
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net cash used in operations					100,000
Net decrease in cash and cash equivalents					100,000
Topic 606
Basis Of Presentation And Significant Accounting Policies [Line Items]
Cumulative-effect adjustment to retained earnings						$ 0
Topic 606 | Difference effect of change - higher (lower)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Revenue recognition		$ 0		$ 0
Selling, general and administrative expense
Basis Of Presentation And Significant Accounting Policies [Line Items]
Prior period reclassification adjustment			700,000		1,200,000
Total operating expense
Basis Of Presentation And Significant Accounting Policies [Line Items]
Prior period reclassification adjustment			$ 700,000		$ 1,200,000

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations [Abstract]
Cash and cash equivalents	$ 63,897	$ 69,418	$ 112,616	$ 163,620
Restricted cash	3,111	2,475	2,475	2,375
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	$ 67,008	$ 71,893	$ 115,091	$ 165,995

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Detail) - shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Antidilutive securities to purchase common stock	19,775,000	20,154,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-based Compensation Expense Included in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 20,169	$ 19,698	$ 61,163	$ 53,513
Cost of product sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	838	1,210	3,025	2,971
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	8,066	6,877	23,617	18,598
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 11,265	$ 11,611	$ 34,521	$ 31,944

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw material	$ 3,005	$ 4,084
Finished goods	897	1,164
Work in process	445
Inventory	$ 4,347	$ 5,248

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued compensation and benefits	$ 14,467	$ 15,260
Accrued consulting and professional fees	9,003	9,395
Accrued research and development services	8,978	9,487
Accrued sales allowances	3,485	3,591
Other	2,919	2,511
Accrued liabilities	$ 38,852	$ 40,244

Investments - Carrying Value an

Investments - Carrying Value and Amortized Cost of Company's Investments Summarized by Major Security Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Debt securities, Estimated Fair Value	$ 150,239	$ 271,924
Equity securities, Amortized Cost	3,149
Equity securities, Unrealized Losses	(1,967)
Equity securities, Estimated Fair Value	1,182
Debt and equity securities, Amortized Cost	153,712	272,331
Debt and equity securities, Unrealized Gains	6	1
Debt and equity securities, Unrealized Losses	(2,297)	(408)
Debt and equity securities, Estimated Fair Value	151,421	271,924
U.S. Treasury notes
Schedule of Available-for-sale Securities [Line Items]
Debt securities, Amortized Cost		32,976
Debt securities, Unrealized Losses		(12)
Debt securities, Estimated Fair Value		32,964
Government sponsored enterprise securities
Schedule of Available-for-sale Securities [Line Items]
Debt securities, Amortized Cost		10,082
Debt securities, Unrealized Losses		(10)
Debt securities, Estimated Fair Value		10,072
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Debt securities, Amortized Cost	124,521	138,650
Debt securities, Unrealized Gains	5	1
Debt securities, Unrealized Losses	(318)	(321)
Debt securities, Estimated Fair Value	124,208	138,330
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Debt securities, Amortized Cost	26,042	90,623
Debt securities, Unrealized Gains	1
Debt securities, Unrealized Losses	(12)	(65)
Debt securities, Estimated Fair Value	$ 26,031	$ 90,558

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Millions	Sep. 30, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
Investments Debt And Equity Securities [Abstract]
Available-for-sale, investment securities held with maturity dates more than one year and less than two years | $	$ 35.1	$ 48.7
Number of securities in unrealized loss position | Security	37	54

Investments - Summary of Gross

Investments - Summary of Gross Unrealized Losses and Fair Value of Available-For-Sale Investments in Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	$ 96,610	$ 263,414
Less Than 12 Months, Unrealized Losses	(201)	(408)
12 Months or Greater, Estimated Fair Value	31,247
12 Months or Greater, Unrealized Losses	(129)
Total, Estimated Fair Value	127,857	263,414
Total, Unrealized Losses	(330)	(408)
U.S. Treasury notes
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value		32,964
Less Than 12 Months, Unrealized Losses		(12)
Total, Estimated Fair Value		32,964
Total, Unrealized Losses		(12)
Government sponsored enterprise securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value		10,072
Less Than 12 Months, Unrealized Losses		(10)
Total, Estimated Fair Value		10,072
Total, Unrealized Losses		(10)
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	81,064	129,820
Less Than 12 Months, Unrealized Losses	(189)	(321)
12 Months or Greater, Estimated Fair Value	28,249
12 Months or Greater, Unrealized Losses	(128)
Total, Estimated Fair Value	109,313	129,820
Total, Unrealized Losses	(317)	(321)
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	15,546	90,558
Less Than 12 Months, Unrealized Losses	(12)	(65)
12 Months or Greater, Estimated Fair Value	2,998
12 Months or Greater, Unrealized Losses	(1)
Total, Estimated Fair Value	18,544	90,558
Total, Unrealized Losses	$ (13)	$ (65)

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Cash Equivalents, Available-For-Sale Investment Securities and Equity Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 206,581	$ 333,541
Money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	55,160	38,057
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	56,342	71,021
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	55,160	38,057
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	150,239	262,520
U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure		32,964
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
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	1,182
Equity securities | 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	1,182
Government sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure		10,072
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
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	124,208	154,396
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	124,208	154,396
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	26,031	98,052
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	$ 26,031	$ 98,052

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	1 Months Ended			9 Months Ended
	Aug. 31, 2016USD ($)shares	Jan. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2012USD ($)$ / sharesshares	Sep. 30, 2018USD ($)$ / shares	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)$ / shares
Class of Stock [Line Items]
Net proceeds from sale of common stock	$ 215,900,000	$ 281,600,000		$ 6,044,000	$ 26,397,000
Share of common stock issued | shares	6,969,696	10,344,827	19,000,000
Common stock, par value | $ / shares				$ 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
Common stock sale price per share | $ / shares			$ 4.43
Expire on December 17, 2019
Class of Stock [Line Items]
Warrants issued | shares			500,000
Warrants issuance price per share | $ / shares			$ 4.42
Warrant exercise price | $ / shares			$ 0.01
Warrant expiration date				Dec. 17, 2019
Issuance of warrant value			$ 2,200,000
Warrants outstanding | shares			500,000
Description of warrant				Per their terms, the warrants to purchase 500,000 shares of common stock, all of which remained outstanding at September 30, 2018, may not be exercised if the holder’s ownership of the Company’s common stock would exceed 19.99 percent following such exercise.
Expire on December 17, 2019 | Risk Free Interest Rate
Class of Stock [Line Items]
Warrants outstanding, measurement input			1.1
Expire on December 17, 2019 | Volatility Percentage
Class of Stock [Line Items]
Warrants outstanding, measurement input			105.8
Expire on December 17, 2019 | Warrant Term
Class of Stock [Line Items]
Warrant term			7 years
Expire on December 17, 2019 | Dividend Yield
Class of Stock [Line Items]
Warrants outstanding, measurement input			0
Registration Rights Agreement
Class of Stock [Line Items]
Common stock, par value | $ / shares		$ 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 | shares	909,090

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Other Commitments [Line Items]
Operating lease, expiration year	2026-01
Restricted cash	$ 3,111,000	$ 2,475,000	$ 2,475,000	$ 2,375,000
Letter of Credit | Corporate Credit Card Program
Other Commitments [Line Items]
Restricted cash	2,000,000
Letter of Credit | Fleet Program
Other Commitments [Line Items]
Restricted cash	$ 700,000
Maximum
Other Commitments [Line Items]
Percentage of royalty payments obligation on net product sales	2.00%

Commitments and Contingencies_2

Commitments and Contingencies - Estimated Annual Future Minimum Payments under Operating Leases (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 748
2,019	1,880
2,020	1,192
2,021	886
2,022	898
Thereafter	2,848
Operating Leases, Future Minimum Payments Due, Total	$ 8,452

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended	9 Months Ended
	Aug. 31, 2018	May 31, 2018	Sep. 30, 2018	Sep. 30, 2018
License Agreements [Line Items]
Loss on strategic investments				$ 1,967,000
Other assets
License Agreements [Line Items]
Aggregate carrying amount of strategic equity investment			$ 1,200,000	1,200,000
Other expense
License Agreements [Line Items]
Loss on strategic investments			1,700,000	2,000,000
Exclusivity Deed | Neuren
License Agreements [Line Items]
Aggregate carrying amount of strategic equity investment		$ 3,100,000
Shares subscribed		1,330,000
Exclusivity Deed | Neuren | Selling, general and administrative expense
License Agreements [Line Items]
Payments for exclusive right		$ 900,000
License Agreements | Neuren | North America
License Agreements [Line Items]
Upfront payment	$ 10,000,000
License Agreements | Neuren | North America | Maximum
License Agreements [Line Items]
Milestone payments payable	$ 455,000,000
License Agreements | Neuren | Research and development | North America
License Agreements [Line Items]
Upfront payment			$ 10,000,000	$ 10,000,000

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Deferred tax benefit or expense related to remeasurement of deferred tax assets and liabilities	$ 0