Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Total revenue		$ 420,494	$ 338,937	$ 261,106
Cost of revenue:
Total cost of revenue	[1]	145,715	116,188	99,380
Operating expenses:
Sales and marketing		55,902	43,490	38,980
General and administrative		95,750	55,396	57,926
Research and development		89,204	72,755	44,272
Amortization and depreciation		21,721	17,734	6,490
Total operating expenses		262,577	189,375	147,668
Operating income		12,202	33,374	14,058
Interest expense		(2,918)	(2,199)	(190)
Other income, net		2,415	1,066	513
Income before income taxes		11,699	32,241	14,381
(Benefit from) / provision for income taxes		(9,825)	2,990	4,227
Net income		21,524	29,251	10,154
Income allocated to participating securities		(3)	(13)	(12)
Net income attributable to common stockholders		$ 21,521	$ 29,238	$ 10,142
Net income per share:
Basic (USD per share)		$ 0.45	$ 0.63	$ 0.22
Diluted (USD per share)		$ 0.43	$ 0.59	$ 0.21
Weighted average common shares outstanding:
Basic (in shares)		47,633,739	46,682,141	45,716,757
Diluted (in shares)		49,692,184	49,153,948	47,875,522
SaaS and license revenue
Revenue:
Total revenue		$ 291,072	$ 236,283	$ 173,540
Cost of revenue:
Total cost of revenue	[1]	44,933	35,610	30,229
Hardware and other revenue
Revenue:
Total revenue		129,422	102,654	87,566
Cost of revenue:
Total cost of revenue	[1]	$ 100,782	$ 80,578	$ 69,151

[1] Exclusive of amortization and depreciation shown in operating expenses below.