Basic and Diluted Net Income (Loss) Per Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2018	2017	2018	2017
Stock options	5,167	3,700	5,167	3,700
Restricted stock units	200	698	200	698
Performance-based restricted stock units (B)	335	1,087	335	1,087
Warrants	6,067	—	6,067
Total equity award shares excluded	11,769	5,485	11,769	5,485

(B) Performance-based restricted stock units are presented based on attainment of 100% of the performance goals being met.

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

A reconciliation of the numerator and the denominator used to calculate basic and diluted net loss per share is as follows (in thousands, except per share amounts):

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018			2017			2018			2017
Numerator
Net loss	$	(4,634	)	$	(7,554	)	$	(11,079	)	$	(17,562	)
Denominator — Basic
Weighted average shares used to calculate net loss per share, basic	39,493			38,966			39,424			38,840
Denominator — Diluted
Weighted average shares used to calculate net loss per share, basic	39,493			38,966			39,424			38,840
Effect of dilutive restricted stock units (A)	—			—			—			—
Effect of dilutive stock options (A)	—			—			—			—
Weighted average shares used to calculate net loss per share, diluted	39,493			38,966			39,424			38,840
Net loss per share
Basic	$	(0.12	)	$	(0.19	)	$	(0.28	)	$	(0.45	)
Diluted	$	(0.12	)	$	(0.19	)	$	(0.28	)	$	(0.45	)