Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Summary of Outstanding Options, Warrants and preferred stock were Excluded from Computation of Diluted Net Loss Per Share

The following outstanding options, restricted stock units and warrants as of December 31 were excluded from the computation of diluted net loss per share for the periods presented because their effect would have been anti-dilutive (in thousands):

	2017	2016	2015
Options to purchase common stock	5,335	4,711	4,069
Restricted stock units	313	115	—
Common stock warrants	317	491	572