Common Stock Reserved for Issuance (Tables)

12 Months Ended

Dec. 31, 2014

Equity [Abstract]

Schedule of Common Stock Reserved for Future Issuance

The common stock reserved for future issuance at December 31, 2013 and 2014 was as follows:

	December 31,
	2013		2014
Conversion of outstanding convertible preferred stock		25,036,330		27,654,928
Shares underlying outstanding stock options		2,723,406		4,248,504
Shares available for future stock option grants		1,848,367		295,101
Warrant to purchase convertible preferred stock		128,231		128,231
Total shares of common stock reserved		29,736,334		32,326,764