Selected Quarterly Financial Data (unaudited) - Schedule of the Impact of the Revision on the Unaudited Quarterly Financial Data (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
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue	$ 59,104	$ 54,673	$ 52,441	$ 48,334	$ 41,782	$ 38,441	$ 35,292	$ 31,762	$ 214,552	$ 147,277	$ 99,129
Gross profit	45,189	40,888	39,429	36,561	30,976	28,488	25,806	23,212	162,067	108,482	70,926
Net loss	$ (17,300)	$ (18,293)	$ (10,725)	$ (8,250)	$ (16,270)	$ (9,727)	$ (13,304)	$ (11,077)	$ (54,568)	$ (50,378)	$ (29,740)
Net loss per common share, basic and diluted	$ (0.65)	$ (0.72)	$ (0.43)	$ (0.34)	$ (0.67)	$ (0.40)	$ (0.56)	$ (0.47)	$ (2.16)	$ (2.11)	$ (1.31)
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue			$ 53,331	$ 47,214	$ 43,155		$ 35,469	$ 30,565		$ 147,293	$ 98,509
Gross profit			40,506	35,484	32,626		25,979	21,954		108,714	70,801
Net loss			$ (11,467)	$ (8,019)	$ (14,713)		$ (12,206)	(11,117)		$ (48,280)	$ (29,420)
Net loss per common share, basic and diluted			$ (0.46)	$ (0.33)	$ (0.61)		$ (0.51)			$ (2.02)	$ (1.30)
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue			$ (890)	$ 1,120	$ (1,373)		$ (177)	1,197		$ (16)	$ 620
Gross profit			(1,077)	1,077	(1,650)		(173)	1,258		(232)	125
Net loss			$ 742	$ (231)	$ (1,557)		$ (1,098)	$ 40		$ (2,098)	$ (320)
Net loss per common share, basic and diluted			$ 0.03	$ (0.01)	$ (0.06)		$ (0.05)			$ (0.09)	$ (0.01)