Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (88,948)	$ (120,299)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt discount and deferred financing	231	1,649
Depreciation and amortization	1,764	991
Stock-based compensation	12,596	12,744
Loss on exchange of convertible debt	0	36,123
Non-cash changes in the fair value of contingent consideration payable	931	1,383
Foreign currency remeasurement loss	10,662	325
Changes in operating assets and liabilities:
Accounts receivable	(8,358)	(1,001)
Inventories	(251)	345
Prepaid expenses and other current assets	4,016	3,059
Accounts payable and accrued expenses	(35,251)	(8,858)
Other non-current assets and liabilities	(5,334)	(3,507)
Deferred reimbursements	0	(1,500)
Net cash used in operating activities	(107,942)	(78,546)
Investing activities
Sale and redemption of marketable securities	106,140	135,187
Purchases of marketable securities	(12,088)	(52,178)
Capital expenditures	(806)	(2,944)
Net cash provided by investing activities	93,246	80,065
Financing activities
Payment of finance leases	(21)	(75)
Purchase of vested restricted stock units	(7,543)	(1,938)
Proceeds from termination of capped call confirmations	0	14,632
Proceeds from exercise of stock options	6,077	3,953
Proceeds of exercise of warrants	0	812
Net cash (used in) provided by financing activities	(1,487)	17,384
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(4,265)	(2,350)
Net (decrease) increase in cash, cash equivalents, and restricted cash at the end of the period	(20,448)	16,553
Cash, cash equivalents, and restricted cash at beginning of period	146,341	82,375
Cash, cash equivalents, and restricted cash at the end of period	125,893	98,928
Supplemental disclosures of cash flow information
Tenant improvements paid through lease incentives	254	0
Cash paid during the period for interest	3,693	4,846
Contingent consideration paid in shares	0	9,316
Capital expenditures unpaid at the end of period	$ 589	$ 0