Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 82,805	$ 72,971	$ 62,254	$ 60,429	$ 64,062	$ 65,703	$ 69,151	$ 68,112	$ 278,459	$ 267,028	$ 241,762
Cost of revenues	40,568	36,902	31,782	29,797	30,767	33,871	34,839	36,322	139,049	135,799	126,267
Gross profit	42,237	36,069	30,472	30,632	33,295	31,832	34,312	31,790	139,410	131,229	115,495
Operating expenses
Research and development	11,862	10,213	9,299	11,814	12,126	9,895	15,189	10,482	43,188	47,692	38,917
Sales and marketing	10,152	8,293	8,035	10,304	11,445	10,363	14,227	10,218	36,784	46,253	42,658
General and administrative	7,176	8,604	6,625	6,446	5,936	5,996	13,063	5,130	28,851	30,125	18,804
Depreciation and amortization	1,601	1,643	1,700	1,695	1,901	1,449	1,227	1,281	6,639	5,858	8,765
Total operating expenses	30,791	28,753	25,659	30,259	31,408	27,703	43,706	27,111	115,462	129,928	109,144
Operating income (loss)	11,446	7,316	4,813	373	1,887	4,129	(9,394)	4,679	23,948	1,301	6,351
Interest expense, net	1,197	1,259	1,525	1,345	1,402	2,105	2,301	2,268	5,326	8,076	8,113
Other expense, net	411	318	(22)	(216)	295	61	56	134	491	546	550
(Loss) income before income taxes	9,838	5,739	3,310	(756)	190	1,963	(11,751)	2,277	18,131	(7,321)	(2,312)
(Benefit) provision for income taxes	(668)	144	(2)	82	1,239	3	8,623	415	(444)	10,280	(799)
Net (loss) income	$ 10,506	$ 5,595	$ 3,312	$ (838)	$ (1,049)	$ 1,960	$ (20,374)	$ 1,862	$ 18,575	$ (17,601)	$ (1,513)
(Loss) earnings per share
Basic									$ 0.72	$ (0.89)	$ (0.11)
Diluted									$ 0.70	$ (0.89)	$ (0.11)
Weighted-average number of shares outstanding to compute net (loss) earnings per share
Basic									25,707,092	19,741,764	13,600,411
Diluted									26,403,112	19,741,764	13,600,411