Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2014
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, income taxes, and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity date of 90 days or less on the date of purchase to be cash equivalents. The Company invests its cash in bank deposits and money market accounts. Restricted Cash The Company is required to guarantee the credit limit on its corporate credit card with a certificate of deposit of $100,000. The collateral will be released upon the cancellation of the corporate credit card. The Company is required under its facility lease agreement to maintain a line of credit with a bank in the amount of $80,000 for the benefit of the lessor. The line of credit is secured by a cash deposit with the bank. The cash deposit will be released upon expiration of the line of credit. Comprehensive Income (Loss) Comprehensive income (loss) is composed of two components: net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that under GAAP are recorded as an element of stockholders’ equity (deficit), but are excluded from net income (loss). The Company did not record any transactions within other comprehensive income (loss) in the periods presented and, therefore, the net income (loss) and comprehensive income (loss) were the same for all periods presented. Revenue Recognition Revenue from research activities made under collaboration partnership agreements are recognized as the services are provided and when there is persuasive evidence that an arrangement exists, delivery has occurred, the price is fixed or determinable, and collectability is reasonably assured. Revenue generated from research and licensing agreements typically includes up-front signing or license fees, cost reimbursements, research services, minimum sublicense fees, milestone payments, and royalties on future licensees’ product sales. For revenue agreements with multiple-element arrangements, such as license and development agreements, the Company allocates revenue to each non-contingent deliverable based on the relative selling price of each deliverable. When applying the relative selling price method, the Company determines the selling price for each deliverable using vendor-specific objective evidence or third-party evidence. If neither exists, the Company uses its best estimate of selling price for that deliverable. Revenue allocated is then recognized when the four basic revenue recognition criteria are met for each deliverable. The Company recognizes revenue from upfront payments ratably over the term of its estimated period of performance under the agreement which is recorded as licensing revenue. Reimbursements for development costs incurred under the Company’s license agreement with AstraZeneca are classified as collaborative development revenue. The Company recognizes cost reimbursement revenue under collaboration partnership agreements as the related research and development costs for services are rendered. Deferred revenue represents the portion of research or license payments received which has not been earned. Revenues from milestones, if they are nonrefundable and deemed substantive, are recognized upon successful accomplishment of the milestones. To the extent that non-substantive milestones are achieved and the Company has remaining performance obligations, milestones are deferred and recognized as revenue over the estimated remaining period of performance. The Company will recognize revenue associated with the non-substantive milestones upon achievement of the milestone if there are no undelivered elements and it has no remaining performance obligations. The Company will account for sales-based milestones as royalties that will be recognized as revenue upon achievement of the milestone. Net Income (Loss) per Share Attributable to Common Stockholders Basic net income (loss) per share attributable to common stockholders is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Prior to the Company’s IPO of its common stock, the Company’s Series A and Series B convertible preferred stock was entitled to receive dividends of up to $0.8181 and $0.2781 per share, respectively, prior and in preference to any declaration or payment of any dividend on common stock and thereafter participate pro rata on an as converted basis with the common stock holders on any distributions to common stockholders. The convertible preferred shares were therefore considered to be participating securities. As a result, the Company calculated the net income (loss) per share using the two-class method. Accordingly, the net income (loss) attributable to common stockholders is derived from the net income (loss) for the period and, in periods in which the Company has net income attributable to common stockholders, an adjustment is made for the noncumulative dividends and allocations of earnings to participating securities based on their outstanding shareholder rights. Under the two-class method, the net loss attributable to common stockholders is not allocated to the convertible preferred stock as the convertible preferred stock did not have a contractual obligation to share in the Company’s losses. The diluted net income per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. In periods when we have incurred a net loss, convertible preferred stock, options to purchase common stock and convertible preferred stock warrants are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is antidilutive. Recent Accounting Pronouncement In July 2013, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update (“ASU”) 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The ASU concludes an unrecognized tax benefit should be presented as a reduction of a deferred tax asset when settlement in this manner is available under the law. The Company adopted this amendment as of January 1, 2014, which did not have a significant impact on the balance sheet. In May 2014, the FASB issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which converges the FASB and the International Accounting Standards Board standards on revenue recognition. Areas of revenue recognition that will be affected include, but are not limited to, transfer of control, variable consideration, allocation of transfer pricing, licenses, time value of money, contract costs and disclosures. This guidance is effective for the fiscal years and interim reporting periods beginning after December 15, 2016, at which time the Company may adopt the new standard under the full retrospective method or the modified retrospective method. Early adoption is not permitted. The Company has not yet selected a transition method nor has the Company determined the impact of the new standard on its financial statements and related disclosures.

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, income taxes, and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments purchased with an original maturity date of 90 days or less on the date of purchase to be cash equivalents. The Company invests its cash in bank deposits and money market accounts.

Restricted Cash

The Company is required to guarantee the credit limit on its corporate credit card with a certificate of deposit of $100,000. The collateral will be released upon the cancellation of the corporate credit card.

The Company is required under its facility lease agreement to maintain a line of credit with a bank in the amount of $80,000 for the benefit of the lessor. The line of credit is secured by a cash deposit with the bank. The cash deposit will be released upon expiration of the line of credit.

Comprehensive Income (Loss)

Comprehensive income (loss) is composed of two components: net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that under GAAP are recorded as an element of stockholders’ equity (deficit), but are excluded from net income (loss). The Company did not record any transactions within other comprehensive income (loss) in the periods presented and, therefore, the net income (loss) and comprehensive income (loss) were the same for all periods presented.

Revenue Recognition

Revenue from research activities made under collaboration partnership agreements are recognized as the services are provided and when there is persuasive evidence that an arrangement exists, delivery has occurred, the price is fixed or determinable, and collectability is reasonably assured. Revenue generated from research and licensing agreements typically includes up-front signing or license fees, cost reimbursements, research services, minimum sublicense fees, milestone payments, and royalties on future licensees’ product sales.

For revenue agreements with multiple-element arrangements, such as license and development agreements, the Company allocates revenue to each non-contingent deliverable based on the relative selling price of each deliverable. When applying the relative selling price method, the Company determines the selling price for each deliverable using vendor-specific objective evidence or third-party evidence. If neither exists, the Company uses its best estimate of selling price for that deliverable. Revenue allocated is then recognized when the four basic revenue recognition criteria are met for each deliverable.

The Company recognizes revenue from upfront payments ratably over the term of its estimated period of performance under the agreement which is recorded as licensing revenue. Reimbursements for development costs incurred under the Company’s license agreement with AstraZeneca are classified as collaborative development revenue. The Company recognizes cost reimbursement revenue under collaboration partnership agreements as the related research and development costs for services are rendered. Deferred revenue represents the portion of research or license payments received which has not been earned.

Revenues from milestones, if they are nonrefundable and deemed substantive, are recognized upon successful accomplishment of the milestones. To the extent that non-substantive milestones are achieved and the Company has remaining performance obligations, milestones are deferred and recognized as revenue over the estimated remaining period of performance. The Company will recognize revenue associated with the non-substantive milestones upon achievement of the milestone if there are no undelivered elements and it has no remaining performance obligations. The Company will account for sales-based milestones as royalties that will be recognized as revenue upon achievement of the milestone.

Net Income (Loss) per Share Attributable to Common Stockholders

Basic net income (loss) per share attributable to common stockholders is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Prior to the Company’s IPO of its common stock, the Company’s Series A and Series B convertible preferred stock was entitled to receive dividends of up to $0.8181 and $0.2781 per share, respectively, prior and in preference to any declaration or payment of any dividend on common stock and thereafter participate pro rata on an as converted basis with the common stock holders on any distributions to common stockholders. The convertible preferred shares were therefore considered to be participating securities. As a result, the Company calculated the net income (loss) per share using the two-class method. Accordingly, the net income (loss) attributable to common stockholders is derived from the net income (loss) for the period and, in periods in which the Company has net income attributable to common stockholders, an adjustment is made for the noncumulative dividends and allocations of earnings to participating securities based on their outstanding shareholder rights. Under the two-class method, the net loss attributable to common stockholders is not allocated to the convertible preferred stock as the convertible preferred stock did not have a contractual obligation to share in the Company’s losses. The diluted net income per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. In periods when we have incurred a net loss, convertible preferred stock, options to purchase common stock and convertible preferred stock warrants are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to common stockholders as their effect is antidilutive.

Recent Accounting Pronouncement

In July 2013, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update (“ASU”) 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The ASU concludes an unrecognized tax benefit should be presented as a reduction of a deferred tax asset when settlement in this manner is available under the law. The Company adopted this amendment as of January 1, 2014, which did not have a significant impact on the balance sheet.

In May 2014, the FASB issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which converges the FASB and the International Accounting Standards Board standards on revenue recognition. Areas of revenue recognition that will be affected include, but are not limited to, transfer of control, variable consideration, allocation of transfer pricing, licenses, time value of money, contract costs and disclosures. This guidance is effective for the fiscal years and interim reporting periods beginning after December 15, 2016, at which time the Company may adopt the new standard under the full retrospective method or the modified retrospective method. Early adoption is not permitted. The Company has not yet selected a transition method nor has the Company determined the impact of the new standard on its financial statements and related disclosures.