Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (28,578)	$ (13,844)	$ (14,193)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	4,156	3,328	2,180
Stock-based compensation	34,961	19,835	12,938
Amortization of deferred commissions	13,185	12,591	9,525
Capital gain from disposal of fixed assets	(27)	(20)	(2)
Prepaid expenses and other current assets
Deferred commissions	(7,627)	(21,735)	(6,425)
Other long term assets	(1,932)	(3,317)	(1,028)
Deferred commissions	(15,308)	(14,742)	(11,817)
Other long term assets	(270)	0	0
Trade payables	1,985	(653)	(1,324)
Accrued expenses and other short term liabilities	9,910	14,453	5,302
Deferred revenues	14,115	20,860	11,860
Other long term liabilities	(1,025)	(405)	331
Net cash provided by operating activities	23,545	16,351	7,347
Cash flows from investing activities:
Decrease (increase) in short-term deposits	(30,280)	25,329	(8,390)
Increase in marketable securities	(39)	(39,731)	0
Increase in long-term deposits	(313)	(305)	(111)
Proceeds from sale of property and equipment	27	20	2
Purchase of property and equipment	(9,583)	(5,314)	(3,825)
Net cash used in investing activities	(40,188)	(20,001)	(12,324)
Cash flows from financing activities:
Proceeds from employee stock plans, net	8,114	12,083	4,072
Net cash provided by financing activities	8,114	12,083	4,072
Increase (decrease) in cash, cash equivalents and restricted cash	(8,529)	8,433	(905)
Cash, cash equivalents and restricted cash at beginning of period	57,236	48,803	49,708
Cash, cash equivalents and restricted cash at end of period	48,707	57,236	48,803
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 710	$ 469	$ 246