CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES:
Net loss	$ (18,890)	$ (3,203)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,166	2,438
Depreciation	3,881	3,358
Amortization of purchased intangibles	746	711
Amortization of debt issuance costs	116	0
Accretion of debt discount on convertible senior notes	727	0
Amortization of tenant allowance	(129)	(42)
Deferred income taxes	52	16
Provision for doubtful accounts	502	496
Changes in operating assets and liabilities:
Accounts receivable	(5,763)	(8,467)
Prepaid expenses and other current assets	(6,677)	(5,841)
Other assets	(115)	(21)
Accounts payable	(744)	(172)
Accrued expenses and other current liabilities	(17,932)	(9,782)
Deferred revenue	11,150	19,921
Other liabilities	219	(89)
Net cash used in operating activities	(25,691)	(677)
INVESTING ACTIVITIES:
Purchases of property and equipment, including capitalized software	(8,335)	(4,595)
Cash held as collateral for foreign exchange forward contracts	0	1,235
Payments for acquisitions and intangible assets, net of cash acquired	(2)	(263)
Net cash used in investing activities	(8,337)	(3,623)
FINANCING ACTIVITIES:
Proceeds from issuance of convertible senior notes	230,000	0
Payment of debt issuance costs	(7,329)	0
Purchase of capped call	(23,184)	0
Payments related to contingent consideration	(487)	0
Proceeds from issuance of common stock in connection with the exercise of options	7,198	5,949
Repurchase of common stock	(709)	(1,345)
Net cash provided by financing activities	205,489	4,604
EFFECT OF FOREIGN EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(123)	1,061
CHANGE IN CASH AND CASH EQUIVALENTS	171,338	1,365
CASH AND CASH EQUIVALENTS - Beginning of the period	66,449	56,115
CASH AND CASH EQUIVALENTS - End of the period	237,787	57,480
SUPPLEMENTAL DISCLOSURE OF OTHER CASH FLOW INFORMATION:
Cash paid for income taxes	338	553
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment recorded in accounts payable	198	292
Debt offering costs, accrued but not paid	1,306	0
BotCentral
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Issuance of 85,861 shares of common stock in connection with the BotCentral transaction on January 24, 2018	$ 0	$ 1,000
Issuance of 85,861 shares of common stock in connection with the BotCentral transaction on January 24, 2018 (in shares)	0	85,861