Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Common Stock Excluded from Calculation of Diluted Net Loss Per Share

Potentially dilutive securities that were not included in the diluted net loss per share calculations because they would be anti-dilutive were as follows (in thousands):

	September 30,
	2018		2017
Options to purchase common stock		4,534		3,542
Employee stock plan purchases		116		93
Total		4,650		3,635