Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (47,951)	$ (40,699)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	564	487
Amortization and accretion	(2,105)	22
Stock-based compensation	12,620	8,719
Other non-cash	(186)	150
Changes in operating assets and liabilities
Accounts receivable, net	(12,043)	0
Inventory	33	(969)
Prepaid, current and other assets	(1,391)	(1,628)
Accounts payable, accrued expenses and other current liabilities	(1,267)	(6,873)
Operating lease liabilities	(1,123)	0
Net cash used in operating activities	(48,639)	(40,835)
Cash flows from investing activities
Purchase of available-for-sale investments	0	(56,195)
Proceeds from sales and maturities of investments	0	23,775
Purchase of property, plant and equipment	(4,939)	(9,126)
Net cash used in investing activities	(4,939)	(41,546)
Cash flows from financing activities
Proceeds from sale of common stock, net	0	135,972
Payments related to issuance of stock for stock-based compensation arrangements, net	(599)	(1,420)
Proceeds from exercise of warrants	375	0
Other financing	(148)	(239)
Net cash (used in) provided by financing activities	(372)	134,313
Net change in cash and cash equivalents	(53,950)	51,932
Cash and cash equivalents, at beginning of period	202,818	197,569
Cash and cash equivalents, at end of period	148,868	249,501
Non-cash investing activities
Purchases of property, plant and equipment	$ 1,608	$ 11,413