Common Stock (Tables)

12 Months Ended

Dec. 31, 2015

Stockholders Equity Note [Abstract]

Schedule of Common Stock Reserved for Issuance

As of December 31, 2015 and 2014, we reserved shares of common stock for issuance as follows:

	As of December 31,
	2015	2014
Options outstanding	11,498,747	16,435,568
Unvested restricted stock units outstanding	7,832,962	478,789
Unvested restricted stock outstanding	—	93,805
Unvested early exercised stock options	12,428	117,187
Shares available for grant under Equity Incentive Plan and Inducement Plan	6,672,236	7,392,158
Shares available for purchase under Employee Stock Purchase Plan	1,561,929	2,071,428
Total	27,578,302	26,588,935