Restatement of Previously Issued Consolidated Financial Statements - Summary Impacts Of The Restatement Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained deficit	$ (60,307)	$ (52,773)	$ (59,953)	$ (66,099)	$ (76,013)	$ (84,110)	$ (95,387)	$ (108,058)	$ (59,953)	$ (95,387)	$ (52,773)	$ (84,110)	$ (60,307)	$ (76,013)		$ (115,233)
Total Stockholders' Equity	128,688	130,788	128,885	120,065	109,596	100,657	91,189	83,572	128,885	91,189	130,788	100,657	128,688	109,596	$ 72,323	65,835
Income before provision for income taxes	(7,669)	7,676	8,376	13,173	8,465	11,102	17,015	12,994	21,549	30,009	29,225	41,111	21,556	49,576	12,798
Net (loss) income	$ (7,534)	7,180	6,146	9,986	8,097	11,277	12,671	9,444	16,132	22,115	23,312	33,392	$ 15,778	41,489	(2,269)
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained deficit		(43,816)	(52,336)	(59,513)	(70,571)	(79,452)	(92,035)	(105,230)	(52,336)	(92,035)	(43,816)	(79,452)		(70,571)		(113,378)
Total Stockholders' Equity		139,745	136,502	126,651	115,038	105,315	94,541	86,400	136,502	94,541	139,745	105,315		115,038	74,742	67,690
Income before provision for income taxes		9,436	9,723	14,644	9,485	12,801	17,696	13,526	24,367	31,222	33,803	44,023		53,508	13,645
Net (loss) income		8,520	7,177	11,130	8,881	12,583	13,195	9,853	18,307	23,048	26,827	35,631		44,512	(1,705)
Restatement Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained deficit		(8,957)	(7,617)	(6,586)	(5,442)	(4,658)	(3,352)	(2,828)	(7,617)	(3,352)	(8,957)	(4,658)		(5,442)	(2,400)	(1,855)
Total Stockholders' Equity		(8,957)	(7,617)	(6,586)	(5,442)	(4,658)	(3,352)	(2,828)	(7,617)	(3,352)	(8,957)	(4,658)		(5,442)	(2,419)	$ (1,855)
Income before provision for income taxes		(1,760)	(1,347)	(1,471)	(1,020)	(1,699)	(681)	(532)	(2,818)	(1,213)	(4,578)	(2,912)		(3,932)	(847)
Net (loss) income		$ (1,340)	$ (1,031)	$ (1,144)	$ (784)	$ (1,306)	$ (524)	$ (409)	$ (2,175)	$ (933)	$ (3,515)	$ (2,239)		(3,023)	(564)
Restatement Adjustments | Understatement of cost of revenues and PPE adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before provision for income taxes														(4,080)	0
Net (loss) income														(3,135)	0
Error corrections | Understatement of cost of revenues and PPE adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before provision for income taxes														148	(847)
Net (loss) income														$ 112	$ (564)