Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net loss	$ (2,998)	$ (11,805)	$ (5,584)	$ (26,009)
Shares used in computing net loss per share:
Weighted-average basic shares outstanding (in shares)	21,702	18,594	20,171	18,538
Effect of dilutive securities (in shares)	0	0	0	0
Weighted average common shares outstanding-diluted (in shares)	21,702	18,594	20,171	18,538
Loss per common share:
Loss per share of common stock — basic (in dollars per share)	$ (0.14)	$ (0.63)	$ (0.28)	$ (1.40)
Loss per share of common stock — diluted (in dollars per share)	$ (0.14)	$ (0.63)	$ (0.28)	$ (1.40)
Antidilutive shares (in shares)	1,100	3,900	2,700	4,000