CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (15,586)	$ (37,565)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	576	2,226
Stock-based compensation expense	3,453	4,862
Change in fair value of contingent consideration	1,767
Changes in operating assets and liabilities:
Accounts receivable	4,737	(10,956)
Prepaid expenses and other assets	338	1,789
Accounts payable	(4,317)	(197)
Accrued expenses	2,227	8,523
Net cash used in operating activities	(6,805)	(31,318)
Cash flows from investing activities:
Purchases of property and equipment	(124)	(284)
Purchases of marketable securities	(8,869)	(73,100)
Proceeds from sales and maturities of marketable securities	22,935	82,000
Net cash provided by (used in) investing activities	13,942	8,616
Cash flows from financing activities:
Proceeds from debt financing, net of issuance costs	10,950
Finance lease payments	(57)	(120)
Proceeds from the issuance of stock	25
Net cash (used in) provided by financing activities	10,918	(120)
Net increase (decrease) in cash and cash equivalents	18,055	(22,822)
Cash, cash equivalents and restricted cash at beginning of period	35,937	57,019
Cash, cash equivalents and restricted cash at end of period	53,992	34,197
Supplemental disclosure of non-cash investing and financing activities:
Additions to property and equipment included in accounts payable	16	24
Offering costs included in accounts payable	$ 30
Operating lease asset recorded as a result of new accounting standard		$ 2,132