Basis of Presentation and Significant Accounting Policies	9 Months Ended
Sep. 30, 2016
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 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, 2015 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. Accounts Receivable Accounts receivable are recorded net of customer allowances for prompt payment discounts, distribution fees, chargebacks, and doubtful accounts. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. To date, the Company has determined that an allowance for doubtful accounts is not required. Inventory Inventory, consisting of raw material and finished goods, is stated at the lower of cost or estimated net realizable value. The Company uses a combination of standard and actual costing methodologies to determine the cost basis for its inventories which approximates actual costs. Inventory is valued on a first-in, first-out basis and includes third-party manufacturing costs, freight, and indirect overhead costs. The Company capitalizes inventory costs associated with its products upon regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. Prior to FDA approval of NUPLAZID, all costs related to the manufacturing of NUPLAZID were charged to research and development expense in the period incurred. At September 30, 2016 the Company had an immaterial amount of zero cost raw material that was available for use in the manufacturing of commercial product. The Company provides reserves for potentially excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand and any firm purchase orders, as well as product shelf life. To date, the Company has determined that a reserve for potentially excess, dated or obsolete inventory is not required. 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 has 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 $369,000 and $615,000 for the three and nine months ended September 30, 2016, respectively. As of September 30, 2016, estimated future amortization expense related to the Company’s intangible asset was $369,000 for the remainder of 2016, $1.5 million for each of 2017, 2018, 2019, and 2020, and $1.1 million thereafter. Royalty expense incurred in connection with the Company’s license agreement with the Ipsen Group, as disclosed in Note 9, Commitments and Contingencies, is recorded 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 and are recognized when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred and title to the product and associated risk of loss has passed to the customer, (iii) the price is fixed or determinable, and (iv) collectability is reasonably assured. NUPLAZID was approved by the FDA on April 29, 2016 and the Company commenced shipments of NUPLAZID to specialty pharmacies (“SPs”) and specialty distributors (“SDs”) in late May 2016. Through September 30, 2016, the Company has determined it does not have the necessary volume of activity to reasonably estimate certain sales allowances at the time title and risk of loss transfers to the SP or SD. Accordingly, the price is not considered fixed or determinable at that time. Therefore, the Company recognizes revenue once the SP has filled a patient’s prescription for NUPLAZID or the SD sells NUPLAZID. This approach is frequently referred to as the “sell-through” revenue recognition model. Under the sell-through approach, revenue is recognized when the SP dispenses product to a patient based on the fulfillment of a prescription or the SD sells product to a government facility, long-term care pharmacy or in-patient hospital pharmacy. As of September 30, 2016, the Company had a deferred revenue balance of $1.9 million, net of distribution fees, related to NUPLAZID product sales. The Company recognizes revenue from product sales net of allowances for distribution fees, rebates, chargebacks, and co-payment assistance.

2. Basis of Presentation and Significant Accounting Policies

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, 2015 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.

Accounts Receivable

Accounts receivable are recorded net of customer allowances for prompt payment discounts, distribution fees, chargebacks, and doubtful accounts. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. To date, the Company has determined that an allowance for doubtful accounts is not required.

Inventory

Inventory, consisting of raw material and finished goods, is stated at the lower of cost or estimated net realizable value. The Company uses a combination of standard and actual costing methodologies to determine the cost basis for its inventories which approximates actual costs. Inventory is valued on a first-in, first-out basis and includes third-party manufacturing costs, freight, and indirect overhead costs. The Company capitalizes inventory costs associated with its products upon regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. Prior to FDA approval of NUPLAZID, all costs related to the manufacturing of NUPLAZID were charged to research and development expense in the period incurred. At September 30, 2016 the Company had an immaterial amount of zero cost raw material that was available for use in the manufacturing of commercial product. The Company provides reserves for potentially excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand and any firm purchase orders, as well as product shelf life. To date, the Company has determined that a reserve for potentially excess, dated or obsolete inventory is not required.

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 has 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 $369,000 and $615,000 for the three and nine months ended September 30, 2016, respectively. As of September 30, 2016, estimated future amortization expense related to the Company’s intangible asset was $369,000 for the remainder of 2016, $1.5 million for each of 2017, 2018, 2019, and 2020, and $1.1 million thereafter.

Royalty expense incurred in connection with the Company’s license agreement with the Ipsen Group, as disclosed in Note 9, Commitments and Contingencies, is recorded 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 and are recognized when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred and title to the product and associated risk of loss has passed to the customer, (iii) the price is fixed or determinable, and (iv) collectability is reasonably assured.

NUPLAZID was approved by the FDA on April 29, 2016 and the Company commenced shipments of NUPLAZID to specialty pharmacies (“SPs”) and specialty distributors (“SDs”) in late May 2016. Through September 30, 2016, the Company has determined it does not have the necessary volume of activity to reasonably estimate certain sales allowances at the time title and risk of loss transfers to the SP or SD. Accordingly, the price is not considered fixed or determinable at that time. Therefore, the Company recognizes revenue once the SP has filled a patient’s prescription for NUPLAZID or the SD sells NUPLAZID. This approach is frequently referred to as the “sell-through” revenue recognition model. Under the sell-through approach, revenue is recognized when the SP dispenses product to a patient based on the fulfillment of a prescription or the SD sells product to a government facility, long-term care pharmacy or in-patient hospital pharmacy. As of September 30, 2016, the Company had a deferred revenue balance of $1.9 million, net of distribution fees, related to NUPLAZID product sales.

The Company recognizes revenue from product sales net of allowances for distribution fees, rebates, chargebacks, and co-payment assistance.