View Filing Data

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2015	Jul. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	ACAD
Entity Registrant Name	ACADIA PHARMACEUTICALS INC
Entity Central Index Key	0001070494
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		100,714,851

Condensed Consolidated Balance Sheets - USD ($)
$ in Thousands

Jun. 30, 2015

Dec. 31, 2014

^[1]

Assets

Cash and cash equivalents

$ 93,212

$ 61,854

Investment securities, available-for-sale

177,565

260,632

Interest and other receivables

1,508

964

Prepaid expenses and other current assets

1,108

1,168

Total current assets

273,393

324,618

Property and equipment, net

1,813

553

Other assets

333

287

Total assets

275,539

325,458

Liabilities and stockholders' equity

Accounts payable

2,916

2,016

Accrued liabilities

16,462

13,818

Total current liabilities

19,378

15,834

Long-term liabilities

340

135

Total liabilities

19,718

15,969

Commitments and contingencies (Note 8)

Stockholders' equity:

Preferred stock, $0.0001 par value; 5,000,000 shares authorized at June 30, 2015 and December 31, 2014; no shares issued and outstanding at June 30, 2015 and December 31, 2014

Common stock, $0.0001 par value; 225,000,000 shares and 150,000,000 shares authorized at June 30, 2015 and December 31, 2014, respectively; 100,522,374 shares and 100,047,331 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively

Additional paid-in capital

833,696

807,631

Accumulated deficit

(577,896)

(498,143)

Accumulated other comprehensive income (loss)

(9)

Total stockholders' equity

255,821

309,489

Total liabilities and stockholders' equity

$ 275,539

$ 325,458

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares

Jun. 30, 2015

Dec. 31, 2014

^[1]

Statement of Financial Position [Abstract]

Preferred stock, par value

$ 0.0001

Preferred stock, shares authorized

5,000,000

Preferred stock, shares issued

Preferred stock, shares outstanding

Common stock, par value

$ 0.0001

Common stock, shares authorized

225,000,000

150,000,000

Common stock, shares issued

100,522,374

100,047,331

Common stock, shares outstanding

100,522,374

100,047,331

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues
Collaborative revenues	$ 1	$ 28	$ 5	$ 58
Operating expenses
Research and development (includes stock-based compensation expense of $2,839, $1,089, $5,201, and $2,095, respectively)	18,379	13,799	34,674	25,467
General and administrative (includes stock-based compensation expense of $4,660, $3,242, $16,826, and $5,398, respectively)	21,119	7,952	45,380	14,272
Total operating expenses	39,498	21,751	80,054	39,739
Loss from operations	(39,497)	(21,723)	(80,049)	(39,681)
Interest income, net	119	228	296	358
Net loss	$ (39,378)	$ (21,495)	$ (79,753)	$ (39,323)
Net loss per common share, basic and diluted	$ (0.39)	$ (0.22)	$ (0.80)	$ (0.41)
Weighted average common shares outstanding, basic and diluted	100,349	99,048	100,273	96,042

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense	$ 7,500	$ 4,300	$ 22,027	$ 7,493
Research and development
Stock-based compensation expense	2,839	1,089	5,201	2,095
General and administrative
Stock-based compensation expense	$ 4,660	$ 3,242	$ 16,826	$ 5,398

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net loss	$ (39,378)	$ (21,495)	$ (79,753)	$ (39,323)
Other comprehensive loss:
Unrealized gain on investment securities	8	94	17	46
Foreign currency translation adjustments	(1)		3
Comprehensive loss	$ (39,371)	$ (21,401)	$ (79,733)	$ (39,277)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Thousands

6 Months Ended

Jun. 30, 2015

Jun. 30, 2014

Cash flows from operating activities

Net loss

$ (79,753)

$ (39,323)

Adjustments to reconcile net loss to net cash used in operating activities:

Stock-based compensation

22,027

7,493

Amortization of premiums and accretion of discounts on investment securities, available for sale

(1,115)

(11)

Depreciation

402

Changes in operating assets and liabilities:

Interest and other receivables

(544)

(570)

Prepaid expenses and other current assets

(1,261)

Other assets

(46)

Accounts payable

900

732

Accrued liabilities

2,644

1,654

Deferred revenue

(26)

Long-term liabilities

205

Net cash used in operating activities

(55,220)

(31,149)

Cash flows from investing activities

Purchases of investment securities

(125,255)

(288,639)

Maturities of investment securities

209,454

122,023

Purchases of property and equipment

(1,662)

(6)

Net cash provided by (used in) investing activities

82,537

(166,622)

Cash flows from financing activities

Proceeds from issuance of common stock, net of issuance costs

4,038

199,762

Net cash provided by financing activities

4,038

199,762

Effect of exchange rate changes on cash

Net increase in cash and cash equivalents

31,358

1,991

Cash and cash equivalents

Beginning of period

61,854

^[1]

11,707

End of period

$ 93,212

$ 13,698

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Basis of Presentation	6 Months Ended
Basis of Presentation	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	1. Basis of Presentation The accompanying unaudited condensed consolidated financial statements of ACADIA Pharmaceuticals Inc. should be read in conjunction with the audited financial statements and notes thereto as of and for the year ended December 31, 2014 included in the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“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. The Company has incurred substantial operating losses since its inception due in large part to expenditures for its research and development activities. As of June 30, 2015, the Company had an accumulated deficit of $577.9 million. The Company expects to continue to incur operating losses for at least the next several years as it pursues the development and commercialization of its product candidates. The Company may require significant additional financing in the future to fund its operations. Future capital requirements will depend on many factors, including the progress in, the outcome of and the costs of the Company’s development and regulatory activities, including the ability of the Company to obtain regulatory approval for its products, costs associated with establishing necessary sales and marketing capabilities, the amount of product sales, if any, the scope, prioritization and number of its research and development programs, the ability of its collaborators and the Company to reach milestones and other events or developments under its collaboration and license agreements, and the ability of the Company to enter into new, and to maintain existing, collaboration and license agreements. Unless and until the Company can generate significant cash from operations, it expects to fund its operations through its existing cash, cash equivalents and investment securities, payments from existing and potential future collaborations, proceeds from public or private sales of its equity securities, debt financing, grant funding, or by licensing all or a portion of its product candidates or technology. The Company cannot be certain that adequate additional funding will be available on acceptable terms, or at all. Conditions in the financial markets and other factors could have a material adverse effect on the Company’s ability to access sufficient funding on acceptable terms, or at all. If the Company needs but cannot raise adequate additional capital, it will be required to delay, reduce the scope of, or eliminate one or more of its research or development programs or its commercialization efforts. In such circumstances, the Company may also be required to relinquish greater, or even all, rights to product candidates at earlier stages of development or commercialization or on less favorable terms than it would otherwise choose.

Net Loss Per Share

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

Net Loss Per Share

2. 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 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.

Shares used in calculating basic and diluted net loss per common share exclude the following potential common shares as their effect is antidilutive (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Antidilutive options to purchase common stock		10,024		7,772		9,328		7,629
Antidilutive warrants to purchase common stock		1,966		1,966		1,966		1,966

		11,990		9,738		11,294		9,595

Stock-Based Compensation	6 Months Ended
Stock-Based Compensation	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	3. 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, including the effect of estimated forfeitures, is then expensed over the requisite service period, which is generally the vesting period. The Company recognized stock-based compensation expense of $7.5 million and $22.0 million during the three and six months ended June 30, 2015, respectively, and $4.3 million and $7.5 million during the three and six months ended June 30, 2014, respectively. During the first quarter of 2015, the Company entered into a transition agreement with Uli Hacksell, Ph.D., the Company’s former Chief Executive Officer, in connection with his retirement from the Company in March 2015. Stock-based compensation expense for the first quarter of 2015 included a one-time $9.0 million charge representing the fair value of the outstanding options expected to vest over the term of the transition agreement as valued on the retirement date. As of June 30, 2015, total unrecognized compensation cost related to stock options and purchase plan rights was approximately $86.2 million, which is expected to be recognized over a weighted-average period of 3.1 years.

Accrued Liabilities

6 Months Ended

Jun. 30, 2015

Payables and Accruals [Abstract]

Accrued Liabilities

4. Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):


	June 30, 2015		December 31, 2014
Accrued research and development services	$	7,585	$	7,814
Accrued compensation and benefits		3,528		4,167
Accrued consulting and professional fees		3,666		1,497
Other		1,683		340

	$	16,462	$	13,818

Investment Securities

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Investment Securities

5. Investment Securities

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


	June 30, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Government sponsored enterprise securities	$	164,891	$	13	$	(10	)	$	164,894
Corporate debt securities		12,672		—		(1	)		12,671

	$	177,563	$	13	$	(11	)	$	177,565


	December 31, 2014
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	2,748	$	2	$	—		$	2,750
Government sponsored enterprise securities		97,237		8		(10	)		97,235
Corporate debt securities		137,682		3		(37	)		137,648
Commercial paper		22,980		19		—			22,999

	$	260,647	$	32	$	(47	)	$	260,632

At each reporting date, the Company performs an evaluation of impairment to determine if the 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 June 30, 2015 and December 31, 2014. As of June 30, 2015 and December 31, 2014, all of the Company’s available-for-sale investment securities had contractual maturity dates of less than one year.

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Fair Value Measurements

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

6. Fair Value Measurements

As of June 30, 2015, the Company held $270.5 million of cash equivalents and available-for-sale investment securities consisting of a money market fund and high quality, marketable debt instruments of corporations, financial institutions 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 June 30, 2015 and December 31, 2014, 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 classifications.

The fair value measurements of the Company’s cash equivalents and available-for-sale investment securities are identified in the following tables (in thousands):


			Fair Value Measurements at Reporting Date Using
	June 30, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	92,977	$	92,977	$	—	$	—
Government sponsored enterprise securities		164,894		—		164,894		—
Corporate debt securities		12,671		—		12,671		—

	$	270,542	$	92,977	$	177,565	$	—


			Fair Value Measurements at Reporting Date Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	48,423	$	48,423	$	—	$	—
U.S. Treasury notes		2,750		2,750		—		—
Government sponsored enterprise securities		110,235		—		110,235		—
Corporate debt securities		137,648		—		137,648		—
Commercial paper		22,999		—		22,999		—

	$	322,055	$	51,173	$	270,882	$	—

- 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

Stockholders' Equity	6 Months Ended
Stockholders' Equity	Jun. 30, 2015
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity *Authorized Shares* In June 2015, following approval by the Company’s stockholders, the Company filed a Certificate of Amendment of its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, which increased the number of authorized shares of common stock of the Company from 150,000,000 to 225,000,000. *Equity Incentive Plan* In June 2015, the Company’s stockholders approved an amendment to its 2010 Equity Incentive Plan, as amended, to, among other things, increase the aggregate number of shares of common stock authorized for issuance under the plan by 5,000,000 shares. *Public Offering* In March 2014, the Company raised net proceeds of $196.8 million from the sale of 7,360,000 shares of its common stock in a public offering, including 960,000 shares sold pursuant to the exercise in full of the underwriters’ over-allotment option.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies *External Services* The Company has entered into agreements with contract research organizations and other external service providers primarily for services in connection with the development and planned commercialization of its product candidates. The Company was contractually obligated for up to approximately $29.7 million of future services under these agreements as of June 30, 2015. The nature of the work being conducted under the Company’s agreements with external service providers is such that, in most cases, the services may be stopped with short notice. In such event, the Company would not be liable for the full amount of the contract. The Company’s actual contractual obligations may vary depending upon several factors, including the progress and results of the underlying studies. *Contingent Regulatory Milestone Payments* In connection with the Company’s 2006 license agreement with the Ipsen Group, pursuant to which the Company licensed certain intellectual property rights that complement its patent portfolio for its serotonin platform, including NUPLAZID™ (pimavanserin), the Company may be obligated in future periods to make certain regulatory milestone payments. These milestone payments may never occur as they are contingent on the achievement of future regulatory events which may never be attained. These one-time payments include $2.5 million payable upon the successful filing of the first regulatory application with the U.S. Food and Drug Administration (“FDA”) and $8.0 million payable upon obtaining the first regulatory approval from the FDA. If NUPLAZID is approved, then the Company would make royalty payments to Ipsen of up to two percent on net product sales, if any. *Legal Proceedings* In March 2015, following the Company’s announcement of the update to the timing of its planned New Drug Application (“NDA”) submission to the FDA for NUPLAZID for the treatment of Parkinson’s disease 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, or the Court, against the Company and certain of its current and former officers. The complaints generally allege 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 seek 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 appoints a lead plaintiff and assigns lead counsel. On May 12, 2015, several putative stockholders filed separate motions to consolidate the two actions and be appointed lead plaintiff. The Court has not yet issued an order on consolidation and lead plaintiff. 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.

Recent Accounting Pronouncements	6 Months Ended
Recent Accounting Pronouncements	Jun. 30, 2015
New Accounting Pronouncement or Change in Accounting Principle, Current Period Disclosures [Abstract]
Recent Accounting Pronouncements	9. Recent Accounting Pronouncements In April 2015, the Financial Accounting Standards Board (“FASB”) issued authoritative guidance related to accounting for fees paid in a cloud computing arrangement. This accounting update provides guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. This guidance is effective for annual reporting periods beginning after December 15, 2015 and early adoption is permitted. The Company adopted this guidance in the first quarter of fiscal 2015 with no significant impact to its consolidated financial statements. In May 2014, the FASB issued authoritative accounting guidance related to revenue from contracts with customers. This guidance is a comprehensive new revenue recognition model that requires a company 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. 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. In accordance with the agreed upon delay, the Company will adopt this guidance on January 1, 2018. Companies may use either a full retrospective or a modified retrospective approach to adopt this guidance. The Company is evaluating which transition approach to use and its impact, if any, on its consolidated financial statements.

Stock-Based Compensation (Policies)	6 Months Ended
Stock-Based Compensation (Policies)	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
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, including the effect of estimated forfeitures, is then expensed over the requisite service period, which is generally the vesting period.

Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2015

Earnings Per Share [Abstract]

Potential Common Shares Excluded in Calculating Basic and Diluted Net Loss Per Common Share

Shares used in calculating basic and diluted net loss per common share exclude the following potential common shares as their effect is antidilutive (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Antidilutive options to purchase common stock		10,024		7,772		9,328		7,629
Antidilutive warrants to purchase common stock		1,966		1,966		1,966		1,966

		11,990		9,738		11,294		9,595

Accrued Liabilities (Tables)

6 Months Ended

Jun. 30, 2015

Payables and Accruals [Abstract]

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):


	June 30, 2015		December 31, 2014
Accrued research and development services	$	7,585	$	7,814
Accrued compensation and benefits		3,528		4,167
Accrued consulting and professional fees		3,666		1,497
Other		1,683		340

	$	16,462	$	13,818

Investment Securities (Tables)

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Investment Securities, All Classified as Available-for-Sale

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


	June 30, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Government sponsored enterprise securities	$	164,891	$	13	$	(10	)	$	164,894
Corporate debt securities		12,672		—		(1	)		12,671

	$	177,563	$	13	$	(11	)	$	177,565


	December 31, 2014
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
U.S. Treasury notes	$	2,748	$	2	$	—		$	2,750
Government sponsored enterprise securities		97,237		8		(10	)		97,235
Corporate debt securities		137,682		3		(37	)		137,648
Commercial paper		22,980		19		—			22,999

	$	260,647	$	32	$	(47	)	$	260,632

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

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

The fair value measurements of the Company’s cash equivalents and available-for-sale investment securities are identified in the following tables (in thousands):


			Fair Value Measurements at Reporting Date Using
	June 30, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	92,977	$	92,977	$	—	$	—
Government sponsored enterprise securities		164,894		—		164,894		—
Corporate debt securities		12,671		—		12,671		—

	$	270,542	$	92,977	$	177,565	$	—


			Fair Value Measurements at Reporting Date Using
	December 31, 2014		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market fund	$	48,423	$	48,423	$	—	$	—
U.S. Treasury notes		2,750		2,750		—		—
Government sponsored enterprise securities		110,235		—		110,235		—
Corporate debt securities		137,648		—		137,648		—
Commercial paper		22,999		—		22,999		—

	$	322,055	$	51,173	$	270,882	$	—

Basis of Presentation - Additional Information (Detail) - USD ($)
$ in Thousands

Jun. 30, 2015

Dec. 31, 2014

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Accumulated deficit

$ (577,896)

$ (498,143)

^[1]

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Potential Common Shares Excluded in Calculating Basic and Diluted Net Loss Per Common Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities to purchase common stock	11,990	9,738	11,294	9,595
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities to purchase common stock	10,024	7,772	9,328	7,629
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities to purchase common stock	1,966	1,966	1,966	1,966

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 7,500		$ 4,300	$ 22,027	$ 7,493
Unrecognized compensation costs	$ 86,200			$ 86,200
Weighted-average period to be recognized				3 years 1 month 6 days
Uli Hacksell
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 9,000
Retirement date				Mar. 31, 2015

Accrued Liabilities (Detail) - USD ($)
$ in Thousands

Jun. 30, 2015

Dec. 31, 2014

Payables and Accruals [Abstract]

Accrued research and development services

$ 7,585

$ 7,814

Accrued compensation and benefits

3,528

4,167

Accrued consulting and professional fees

3,666

1,497

Other

1,683

340

Accrued liabilities

$ 16,462

$ 13,818

^[1]

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Investment Securities, All Classified as Available-for-Sale (Detail) - USD ($)
$ in Thousands

Jun. 30, 2015

Dec. 31, 2014

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

$ 177,563

$ 260,647

Unrealized Gains

Unrealized Losses

(11)

(47)

Estimated Fair Value

177,565

260,632

^[1]

U.S. Treasury notes

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

2,748

Unrealized Gains

Estimated Fair Value

2,750

Government sponsored enterprise securities

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

164,891

97,237

Unrealized Gains

Unrealized Losses

(10)

Estimated Fair Value

164,894

97,235

Corporate debt securities

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

12,672

137,682

Unrealized Gains

Unrealized Losses

(1)

(37)

Estimated Fair Value

$ 12,671

137,648

Commercial paper

Schedule of Available-for-sale Securities [Line Items]

Amortized Cost

22,980

Unrealized Gains

Estimated Fair Value

$ 22,999

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Investment, fair value disclosure	$ 270,542	$ 322,055

Fair Value Measurements of Cash Equivalents and Available-For-Sale Investment Securities (Detail) - USD ($)
$ in Thousands

Jun. 30, 2015

Dec. 31, 2014

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

$ 177,565

$ 260,632

^[1]

Investments, fair value disclosure

270,542

322,055

Money market fund

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Cash equivalents, fair value disclosure

92,977

48,423

Government sponsored enterprise securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

164,894

110,235

U.S. Treasury notes

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

2,750

Corporate debt securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

12,671

137,648

Commercial paper

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

22,999

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

92,977

51,173

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]

Cash equivalents, fair value disclosure

92,977

48,423

Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury notes

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

2,750

Significant Other Observable Inputs (Level 2)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, fair value disclosure

177,565

270,882

Significant Other Observable Inputs (Level 2) | Government sponsored enterprise securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

164,894

110,235

Significant Other Observable Inputs (Level 2) | Corporate debt securities

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

$ 12,671

137,648

Significant Other Observable Inputs (Level 2) | Commercial paper

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Available-for-sale investment securities, fair value disclosure

$ 22,999

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Stockholders' Equity - Additional Information (Detail) - USD ($)
$ in Thousands

1 Months Ended

6 Months Ended

Jun. 30, 2015

Mar. 31, 2014

Jun. 30, 2015

Jun. 30, 2014

Dec. 31, 2014

^[1]

Class of Stock [Line Items]

Common stock, shares authorized

225,000,000

150,000,000

Net proceeds from sale of common stock

$ 196,800

$ 4,038

$ 199,762

Share of common stock issued

7,360,000

Equity Incentive Plan 2010

Class of Stock [Line Items]

Increase in common stock authorized for issuance under 2010 Equity Incentive Plan

5,000,000

Underwriter

Class of Stock [Line Items]

Share of common stock issued

960,000

[1]	The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Commitments and Contingencies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015 USD ($)
Payable upon filing of first regulatory application with U.S Food and Drug Administration, ("FDA")
Other Commitments [Line Items]
One-time contingent regulatory milestone payments related to agreement with Ipsen Group	$ 2,500,000
Payable upon obtaining first regulatory approval from the FDA.
Other Commitments [Line Items]
One-time contingent regulatory milestone payments related to agreement with Ipsen Group	8,000,000
Maximum
Other Commitments [Line Items]
External services	$ 29,700,000
Percentage of royalty payments obligation on net product sales	2.00%