Common Stock Reserved for Issuance (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Schedule of Common Stock Reserved for Future Issuance

The common stock reserved for future issuance at December 31, 2016 and 2015 was as follows:

	December 31,
	2016		2015
Shares underlying outstanding stock options		6,127,291		6,053,672
Shares available for future stock option grants		2,168,391		3,166,968
Shares issuable upon settlement of restricted    stock units outstanding		151,240		—
ESPP shares available for issuance		667,670		285,621
Warrant to purchase common stock		1,707,736		326,991
Total shares of common stock reserved		10,822,328		9,833,252