Stockholders' Equity - Schedule of Activities in Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders Equity [Line Items]
Beginning Balances	$ 34,384	$ 36,073
Issuance of common stock from option exercises	5	16
Stock-based compensation	463	270
Other comprehensive income (loss)	35	(24)
Net loss	(2,262)	(623)
Ending Balances	32,625	36,188
ASU 2014-09
Stockholders Equity [Line Items]
Adjustment		476
Common stock
Stockholders Equity [Line Items]
Beginning Balances	$ 50	$ 50
Beginning Balances (in shares)	49,752,516	49,569,721
Issuance of common stock from option exercises (in shares)	5,708	16,387
Vesting of restricted stock units (in shares)		15,265
Ending Balances	$ 50	$ 50
Ending Balances (in shares)	49,758,224	49,601,373
Additional paid-in capital
Stockholders Equity [Line Items]
Beginning Balances	$ 216,034	$ 214,796
Issuance of common stock from option exercises	5	16
Stock-based compensation	463	270
Ending Balances	216,502	215,082
Retained earnings
Stockholders Equity [Line Items]
Beginning Balances	(181,672)	(178,738)
Net loss	(2,262)	(623)
Ending Balances	(183,934)	(178,885)
Retained earnings | ASU 2014-09
Stockholders Equity [Line Items]
Adjustment		476
Accumulated deficit
Stockholders Equity [Line Items]
Beginning Balances	(28)	(35)
Other comprehensive income (loss)	35	(24)
Ending Balances	$ 7	$ (59)