Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The accompanying condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). To conform with GAAP, the preparation of our financial statements requires management to make judgments, assumptions, and estimates that affect the amounts reported in our condensed financial statements and accompanying notes. Estimates are used for, but not limited to, accruals for clinical trial activity, other accrued liabilities, and assumptions used in determining stock-based compensation expenses and convertible preferred stock warrant liability. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ materially from those estimates. Unaudited Interim Financial Information The accompanying unaudited condensed financial statements as of September 30, 2015 and for the three and nine months ended September 30, 2015 and 2014 and the related interim information contained within the notes to the condensed financial statements are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The results of operations for the three and nine months ended September 30, 2015 are not necessarily indicative of the results to be expected for the year ended December 31, 2015 or for other future interim periods or years. The accompanying unaudited condensed financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2014 included in our Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission (SEC). Segments We operate in one segment and use cash flow as the primary measure to manage our business and do not segment the business for internal reporting or decision-making purposes. Reverse Stock Split On July 14, 2014, we filed an amendment to our amended and restated certificate of incorporation, effecting a 1-for-8.175 reverse stock split. All issued and outstanding stock and per share amounts contained in our condensed financial statements have been retroactively adjusted to reflect this reverse stock split for all periods presented. Follow-On Public Offering In April 2015, we closed an underwritten public offering of 3,000,000 shares of our common stock at a price of $26.50 per share. In May 2015, we sold an additional 47,409 shares directly to our underwriters when they exercised a portion of their option to purchase additional shares at $26.50 per share. We received net proceeds of $75.4 million (inclusive of the exercise of a portion of the underwriters' option to purchase additional shares), after underwriting discounts and commissions and offering expenses totaling $5.4 million. Offering Costs Offering costs represent legal, accounting and other direct costs related to our efforts to raise capital through our follow-on public offering in April 2015 and for our initial public offering (IPO) in July 2014. These costs were deferred until completion of the follow-on public offering and IPO, respectively, at which time they were reclassified to additional paid-in capital as a reduction of the proceeds. Comprehensive Loss Comprehensive loss is comprised of net loss and certain changes in equity that are excluded from net loss. There was no difference between comprehensive loss and net loss for the three and nine months ended September 30, 2015 and 2014. Revenue Recognition We derive our revenue from collaboration and licensing agreements and the sale of products associated with material transfer, collaboration and supply agreements. Licensing fees are recognized when the amounts are earned and determinable during the applicable period. We recognize up-front nonrefundable license fees when due under contractual agreements and when we do not have a continuing obligation to provide services related to the agreement. Revenue associated with nonrefundable up-front license fees under arrangements where the license fees and research and development activities cannot be accounted for as separate units of accounting is deferred and recognized as revenue on a straight-line basis over the expected term of our continued involvement in the research and development process. Revenues from the achievement of research and development milestones, if deemed substantive, are recognized as revenue when the milestones are achieved, and the milestone payments are due and collectible. If not deemed substantive, we recognize such milestones as revenue on a straight-line basis over the remaining expected term of continued involvement in the research and development process. Milestones are considered substantive if all of the following conditions are met: (1) the milestone is nonrefundable, (2) achievement of the milestone was not reasonably assured at the inception of the arrangement, (3) substantive effort is involved to achieve the milestone, and (4) the amount of the milestone appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone and any ongoing research and development or other services are priced at fair value. Payments received in advance of work performed are recorded as unearned revenue. Certain agreements from which we derive our revenue include multiple deliverables. We recognize the revenue for each deliverable at fair value determined to be the estimated selling price in cases when neither vendor specific objective evidence nor third-party evidence is available. Revenue is recognized when all of the following criteria are met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred or services have been rendered, (3) the price to the customer is fixed or determinable and (4) collectability is reasonably assured. The evaluation of these revenue recognition criteria requires significant management judgment. For instance, we use judgment to assess collectability based on factors such as the customer’s creditworthiness and past collection history, if applicable. If we determine that collection of a payment is not reasonably assured, revenue recognition is deferred until receipt of payment. We also use judgment to assess whether a price is fixed or determinable including, but not limited to, reviewing contractual terms and conditions related to payment terms. Revenue from product sales of glucopyranosyl lipid A (GLA), a product from our GLAAS platforms, is recognized when the risk of loss has passed to the customer or deferred until such time that risk of loss has passed. All revenues associated from the sale of GLA products supplied by us are reported under product sales with the applicable costs reported under cost of product sales. Product sales consist of the direct costs associated with the manufacture and formulation of GLA, including costs to purchase raw materials, third-party contract manufacturing costs, assay testing and ongoing product stability testing. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB), issued Accounting Standards Update (ASU) No. 2014-09, related to the recognition of revenue. ASU 2014-09 requires entities to recognize revenue through the application of a five step model, which includes identification of the contract, identification of the performance obligations, determination of the transaction price, allocation of the transaction price to the performance obligations, and recognition of revenue as the entity satisfies the performance obligations. ASU 2014-09 is effective retrospectively for annual or interim reporting periods beginning after December 15, 2017, with early application permitted for annual reporting periods beginning after December 15, 2016. Early adoption prior to that date is not permitted. We are evaluating the guidance to determine the potential impact on our results of operations, financial condition, cash flows, and financial statement disclosures.

Summary of Significant Accounting Policies

Basis of Presentation and Use of Estimates

The accompanying condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). To conform with GAAP, the preparation of our financial statements requires management to make judgments, assumptions, and estimates that affect the amounts reported in our condensed financial statements and accompanying notes. Estimates are used for, but not limited to, accruals for clinical trial activity, other accrued liabilities, and assumptions used in determining stock-based compensation expenses and convertible preferred stock warrant liability. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable. Actual results could differ materially from those estimates.

Unaudited Interim Financial Information

The accompanying unaudited condensed financial statements as of September 30, 2015 and for the three and nine months ended September 30, 2015 and 2014 and the related interim information contained within the notes to the condensed financial statements are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The results of operations for the three and nine months ended September 30, 2015 are not necessarily indicative of the results to be expected for the year ended December 31, 2015 or for other future interim periods or years.

The accompanying unaudited condensed financial statements should be read in conjunction with the audited financial statements for the year ended December 31, 2014 included in our Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission (SEC).

Segments

We operate in one segment and use cash flow as the primary measure to manage our business and do not segment the business for internal reporting or decision-making purposes.

Reverse Stock Split

On July 14, 2014, we filed an amendment to our amended and restated certificate of incorporation, effecting a 1-for-8.175 reverse stock split. All issued and outstanding stock and per share amounts contained in our condensed financial statements have been retroactively adjusted to reflect this reverse stock split for all periods presented.

Follow-On Public Offering

In April 2015, we closed an underwritten public offering of 3,000,000 shares of our common stock at a price of $26.50 per share. In May 2015, we sold an additional 47,409 shares directly to our underwriters when they exercised a portion of their option to purchase additional shares at $26.50 per share. We received net proceeds of $75.4 million (inclusive of the exercise of a portion of the underwriters' option to purchase additional shares), after underwriting discounts and commissions and offering expenses totaling $5.4 million.

Offering Costs

Offering costs represent legal, accounting and other direct costs related to our efforts to raise capital through our follow-on public offering in April 2015 and for our initial public offering (IPO) in July 2014. These costs were deferred until completion of the follow-on public offering and IPO, respectively, at which time they were reclassified to additional paid-in capital as a reduction of the proceeds.

Comprehensive Loss

Comprehensive loss is comprised of net loss and certain changes in equity that are excluded from net loss. There was no difference between comprehensive loss and net loss for the three and nine months ended September 30, 2015 and 2014.

Revenue Recognition

We derive our revenue from collaboration and licensing agreements and the sale of products associated with material transfer, collaboration and supply agreements.

Licensing fees are recognized when the amounts are earned and determinable during the applicable period. We recognize up-front nonrefundable license fees when due under contractual agreements and when we do not have a continuing obligation to provide services related to the agreement. Revenue associated with nonrefundable up-front license fees under arrangements where the license fees and research and development activities cannot be accounted for as separate units of accounting is deferred and recognized as revenue on a straight-line basis over the expected term of our continued involvement in the research and development process. Revenues from the achievement of research and development milestones, if deemed substantive, are recognized as revenue when the milestones are achieved, and the milestone payments are due and collectible. If not deemed substantive, we recognize such milestones as revenue on a straight-line basis over the remaining expected term of continued involvement in the research and development process.

Milestones are considered substantive if all of the following conditions are met: (1) the milestone is nonrefundable, (2) achievement of the milestone was not reasonably assured at the inception of the arrangement, (3) substantive effort is involved to achieve the milestone, and (4) the amount of the milestone appears reasonable in relation to the effort expended, the other milestones in the arrangement and the related risk associated with the achievement of the milestone and any ongoing research and development or other services are priced at fair value. Payments received in advance of work performed are recorded as unearned revenue.

Certain agreements from which we derive our revenue include multiple deliverables. We recognize the revenue for each deliverable at fair value determined to be the estimated selling price in cases when neither vendor specific objective evidence nor third-party evidence is available.

Revenue is recognized when all of the following criteria are met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred or services have been rendered, (3) the price to the customer is fixed or determinable and (4) collectability is reasonably assured. The evaluation of these revenue recognition criteria requires significant management judgment. For instance, we use judgment to assess collectability based on factors such as the customer’s creditworthiness and past collection history, if applicable. If we determine that collection of a payment is not reasonably assured, revenue recognition is deferred until receipt of payment. We also use judgment to assess whether a price is fixed or determinable including, but not limited to, reviewing contractual terms and conditions related to payment terms.

Revenue from product sales of glucopyranosyl lipid A (GLA), a product from our GLAAS platforms, is recognized when the risk of loss has passed to the customer or deferred until such time that risk of loss has passed. All revenues associated from the sale of GLA products supplied by us are reported under product sales with the applicable costs reported under cost of product sales. Product sales consist of the direct costs associated with the manufacture and formulation of GLA, including costs to purchase raw materials, third-party contract manufacturing costs, assay testing and ongoing product stability testing.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (FASB), issued Accounting Standards Update (ASU) No. 2014-09, related to the recognition of revenue. ASU 2014-09 requires entities to recognize revenue through the application of a five step model, which includes identification of the contract, identification of the performance obligations, determination of the transaction price, allocation of the transaction price to the performance obligations, and recognition of revenue as the entity satisfies the performance obligations. ASU 2014-09 is effective retrospectively for annual or interim reporting periods beginning after December 15, 2017, with early application permitted for annual reporting periods beginning after December 15, 2016. Early adoption prior to that date is not permitted. We are evaluating the guidance to determine the potential impact on our results of operations, financial condition, cash flows, and financial statement disclosures.