UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (45,875)	$ (24,774)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	3,875	3,397
Stock-based compensation expense	5,876	4,367
Provisions for doubtful accounts	118	(178)
Non-cash interest expense	22	8
Change in fair value of warrant liability	8,838	(124)
Deferred income taxes	4
Changes in operating assets and liabilities:
Accounts receivable	17,100	(89)
Prepaid expenses and other assets	(2,293)	(1,720)
Deferred commissions	(1,962)	(2,109)
Accounts payable	1,787	1,241
Accrued expenses	(2,773)	(3,535)
Deferred revenue	572	9,898
Deferred rent	23	(74)
Other long-term liabilities	(1)	(55)
Net cash used in operating activities	(14,689)	(13,747)
Cash flows from investing activities:
Purchases of property and equipment	(4,197)	(3,124)
Capitalization of internal-use software costs	(991)	(478)
Net cash used in investing activities	(5,188)	(3,602)
Cash flows from financing activities:
Proceeds from exercise of stock options	2,731	1,729
Repayments of line of credit		(5,500)
Proceeds from initial public offering, net of offering costs	159,617
Payments of deferred financing costs	(47)	(84)
Net cash provided by (used in) financing activities	162,301	(3,855)
Net increase (decrease) in cash and cash equivalents	142,424	(21,204)
Cash and cash equivalents at beginning of period	36,073	51,503
Cash and cash equivalents at end of period	178,497	30,299
Supplemental disclosure of non‑cash investing and financing activities:
Conversion of redeemable convertible preferred stock upon initial public offering	532,696
Conversion of convertible preferred stock upon initial public offering	1,721
Issuance of common stock upon exercise of common stock warrants	11,604
Deferred IPO costs paid in prior periods	1,911
Accretion of preferred stock to redemption value	199,492	8,324
Additions to property and equipment included in accounts payable at period end	$ 249	216
Series B preferred stock issued upon exercise of Series B Warrant		225
Series F preferred stock and common stock issued upon termination of customer warrant in connection with acquisition of Confer Technologies, Inc.		$ 1,347