Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (103,122)	$ (101,549)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,808	2,424
Stock-based compensation expense	7,223	8,659
Amortization of debt discount	770	256
Deferred rent expense		329
Loss (gain) on disposal of assets and impairment charges	224	(62)
Research and development license fees settled with convertible bond and stock		31,545
Deferred income taxes	486	(316)
Changes in operating assets and liabilities:
Receivables, net	(4,217)	1,397
Prepaid expenses and other assets	(17,086)	(6,290)
Inventories	336	(8,670)
Accounts payable and accrued expenses	38,458	(3,038)
Net cash used in operating activities	(74,120)	(75,315)
Cash flows from investing activities:
Purchase of property and equipment	(8,513)	(2,501)
Payments for licenses	(4,175)
Purchases of short-term investments	(57,014)	(110,605)
Sales and maturities of short-term investments	72,290	31,981
Net cash provided by (used in) investing activities	2,588	(81,125)
Cash flows from financing activities:
Proceeds from sale of stock	100,373	122,666
Proceeds from issuance of debt	6,464	50,000
Costs incurred related to the sale of stock	(54)	(5,118)
Costs incurred related to the issuance of debt		(1,593)
Proceeds from exercise of stock options	1,404	2,960
Repayment of finance lease obligations and long-term debt	(136)	(551)
Net cash provided by financing activities	108,051	168,364
Net increase in cash, cash equivalents, and restricted cash	36,519	11,924
Cash, cash equivalents, and restricted cash, beginning of period	49,794	39,284
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	592	(100)
Cash, cash equivalents, and restricted cash, end of period (See Note 3)	86,905	51,108
Supplemental cash flow disclosures
Interest paid	4,415	952
Non-cash investing and financing activities:
Accrued purchases of property and equipment	1,106	445
Cost of equity raise in accounts payable and accrued expenses		400
Common stock issued in lieu of licensing cash payment		$ 31,545
Right-of-use assets recognized in exchange for new operating lease obligations	$ 583