Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Schedule of common stock equivalents excluded due to anti-dilutive effect

	As of September 30,
	2016	2017
Outstanding common stock options	6,544,738	6,265,333
Outstanding warrants	34,647	756,647
Outstanding RSUs	414,018	478,087
Shares to be purchased under the ESPP	34,853	18,323
Total	7,028,256	7,518,390