CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows used in operating activities:
Net loss	$ (74,216)	$ (58,020)	$ (17,037)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	8,270	4,863	2,320
Allowance for doubtful accounts	2,412	2,034	1,308
Stock-based compensation	7,723	3,075	533
Deferred income taxes	510	36	388
Accretion of interest	262	460	106
Amortization of warrants	7,717	798
Changes in operating assets and liabilities:
Accounts receivable	(2,900)	(6,795)	(5,079)
Prepaid expenses and other current assets	(826)	(957)	(436)
Other assets	(42)	5	(185)
Accounts payable	(813)	(612)	2,099
Accrued expenses and other current liabilities	(2,221)	3,457	(26)
Accrued compensation	1,688	2,887	1,971
Other liabilities	641	1,588	2,679
Net cash used in operating activities	(51,795)	(47,181)	(11,359)
Cash flows provided by (used in) investing activities:
Purchase of property and equipment	(2,108)	(6,275)	(1,069)
Purchase of internal software	(1,304)	(1,542)	(665)
Purchase of marketable securities	(44,146)	(103,030)
Proceeds from the liquidation/maturity of marketable securities	110,717	20,411
Acquisition of business, net of cash acquired	(37,013)	(17,767)	(13,844)
Net cash provided by (used in) investing activities	26,146	(108,203)	(15,578)
Cash flows provided by financing activities:
Net proceeds from the exercise of stock options	2,524	428	747
Proceeds from issuance of convertible preferred stock			50,082
Proceeds from borrowing under bank and other debt	34,990	6,800	19,700
Repayment of bank loan and other debt	(17,166)	(6,332)
Proceeds from issuance of common stock under IPO		163,118
Proceeds from issuance of common stock	250
Repurchase of stock			(368)
Net cash provided by financing activities	20,598	164,014	70,161
Net (decrease) increase in cash and cash equivalents	(5,051)	8,630	43,224
Cash and cash equivalents at beginning of the period	55,066	46,436	3,212
Cash and cash equivalents at end of the period	50,015	55,066	46,436
Interest paid	$ 2,387	$ 1,995	$ 1,191