Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Net loss	$ (46,077)	$ (21,928)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	19,357	16,808
Deferred income taxes	168	(207)
Bad debt expense and other reserves	827	1,240
Stock-based compensation	31,382	28,316
Increase in the fair value of contingent consideration liability	225	0
Amortization of lease right-of-use assets	4,437	0
Loss from equity method investment	737	0
Non-cash interest expense on lease financing obligation	0	278
Impairment or write-off and net loss on disposal of finite-lived assets	1,109	294
Changes in operating assets and liabilities:
Accounts receivable	1,326	(9,496)
Prepaid expenses	(1,879)	(3,816)
Other current assets	(30,558)	(915)
Other assets	1,897	(760)
Accounts payable	(4,762)	8,109
Accrued employee expenses	1,740	(1,545)
Operating lease liabilities	(5,125)	0
Accrued expenses and other liabilities	32,799	(508)
Other liabilities	(352)	113
Net cash provided by operating activities	7,251	15,983
Cash flows from investing activities
Purchase of property and equipment	(8,150)	(13,088)
Cash paid for equity method investment	(23,174)	0
Net cash used in investing activities	(31,324)	(13,088)
Cash flows from financing activities
Proceeds from exercise of common stock options	2,857	19,385
Taxes paid related to net share settlement of equity awards	(2,449)	(2,293)
Net cash provided by financing activities	408	17,092
Net (decrease) increase in cash and cash equivalents	(23,665)	19,987
Cash and cash equivalents at beginning of period	196,128	197,762
Cash and cash equivalents at end of period	172,463	217,749
Supplemental disclosures of non-cash activities
Stock-based compensation capitalized for software development	1,409	1,358
Capitalized assets included in accounts payable, accrued employee expenses and other accrued expenses	335	624
Proceeds receivable from disposal of capitalized facility lease	0	700
Taxes payable related to net share settlement of equity awards included in accrued employee expenses	$ 0	$ 39