Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss	$ (141,440)	$ (204,850)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt discount and deferred financing	532	2,104
Depreciation and amortization	3,803	2,145
Stock-based compensation	21,004	22,679
Loss on exchange of convertible debt	0	40,624
Non-cash changes in the fair value of contingent consideration payable	1,646	1,863
Foreign currency remeasurement loss	5,604	530
Changes in operating assets and liabilities:
Accounts receivable	(10,388)	(6,829)
Inventories	1,351	(1,908)
Prepaid expenses and other current assets	1,375	(3,523)
Accounts payable and accrued expenses	(23,916)	12,453
Other non-current assets and liabilities	(1,031)	(819)
Deferred reimbursements	0	(1,500)
Net cash used in operating activities	(141,460)	(137,031)
Investing activities
Sale and redemption of marketable securities	210,139	261,425
Purchases of marketable securities	(45,005)	(191,318)
Capital expenditures	(1,876)	(5,110)
Net cash provided by investing activities	163,258	64,997
Financing activities
Proceeds from issuance of common stock, net of issuance costs	0	188,994
Payment of finance leases	(38)	(98)
Purchase of vested restricted stock units	(8,097)	(2,555)
Proceeds from termination of capped call confirmations	0	19,875
Proceeds from exercise of stock options	10,734	6,760
Proceeds of exercise of warrants	0	812
Net cash provided by financing activities	2,599	213,788
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(3,476)	(941)
Net increase in cash, cash equivalents, and restricted cash at the end of the period	20,921	140,813
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	167,262	223,188
Supplemental disclosures of cash flow information
Tenant improvements paid through lease incentives	455	0
Cash paid during the period for interest	10,709	9,302
Contingent consideration paid in shares	0	9,316
Capital expenditures unpaid at the end of period	$ 502	$ 837