SELECTED UNAUDITED QUARTERLY FINANCIAL INFORMATION - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 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	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 210,032	$ 180,057	$ 134,094	$ 100,150	$ 92,289	$ 78,002	$ 75,896	$ 69,972	$ 624,333	$ 316,159	$ 286,166
Cost of revenues	132,151	115,351	88,775	66,811	64,124	52,738	53,195	51,657	403,088	221,714	230,123
Gross profit	77,881	64,706	45,319	33,339	28,165	25,264	22,701	18,315	221,245	94,445	56,043
Operating expenses:
Research and development	11,168	11,085	9,604	8,524	7,340	8,165	9,462	7,620	40,381	32,587	33,157
Sales and marketing	10,690	9,551	9,054	7,433	6,617	7,375	6,828	6,227	36,728	27,047	23,126
General and administrative	10,450	9,895	8,583	9,880	7,664	7,510	6,969	6,943	38,808	29,086	22,221
Restructuring charges	1,131	469	631	368	1,541	2,588	0	0	2,599	4,129	16,917
Total operating expenses	33,439	31,000	27,872	26,205	23,162	25,638	23,259	20,790	118,516	92,849	95,421
Income (loss) from operations	44,442	33,706	17,447	7,134	5,003	(374)	(558)	(2,475)	102,729	1,596	(39,378)
Interest income	815	894	593	211	490	321	154	93	2,513	1,058	276
Interest expense	(2,303)	(2,286)	(1,351)	(3,751)	(3,095)	(2,790)	(2,423)	(2,385)	(9,691)	(10,693)	(8,212)
Other income (expense)	1,467	(943)	(5,480)	(481)	(1,113)	(379)	(572)	(126)	(5,437)	(2,190)	1,973
Total other expense, net	(21)	(2,335)	(6,238)	(4,021)	(3,718)	(2,848)	(2,841)	(2,418)	(12,615)	(11,825)	(5,963)
Income before income taxes	44,421	31,371	11,209	3,113	1,285	(3,222)	(3,399)	(4,893)	90,114	(10,229)	(45,341)
Income tax benefit (provision)	72,245	(272)	(591)	(348)	(576)	(248)	(339)	(235)	71,034	(1,398)	149
Net income (loss)	$ 116,666	$ 31,099	$ 10,618	$ 2,765	$ 709	$ (3,470)	$ (3,738)	$ (5,128)	$ 161,148	$ (11,627)	$ (45,192)
Net income (loss) per share, basic (in USD per share)	$ 0.95	$ 0.25	$ 0.09	$ 0.03	$ 0.01	$ (0.03)	$ (0.04)	$ (0.06)	$ 1.38	$ (0.12)	$ (0.54)
Net income (loss) per share, diluted (in USD per share)	$ 0.88	$ 0.23	$ 0.08	$ 0.02	$ 0.01	$ (0.03)	$ (0.04)	$ (0.06)	$ 1.23	$ (0.12)	$ (0.54)