Loss per Share (Tables)

3 Months Ended

Mar. 31, 2019

Earnings Per Share [Abstract]

Common Stock Excluded from Calculation of Diluted Earnings Per Share

The following common stock equivalents were excluded from the calculation of diluted net loss per share applicable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:

	Three Months Ended March 31,
	2019	2018
Stock options	6,482,873	6,104,808
Restricted stock units	709,162	405,646
Employee stock purchase plan	6,778	5,289
Total common stock equivalents	7,198,813	6,515,743