Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net loss	$ (181,111,000)	$ (86,592,000)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	1,730,000	916,000
Amortization of debt issuance costs and fees	779,000	230,000
Amortization and accretion of premium or discount on investments, net	54,000	52,000
Stock-based compensation	29,015,000	18,072,000
Induced conversion of convertible notes	24,059,000	0
Unrealized foreign exchange (gain) loss	(207,000)	522,000
Changes in operating assets and liabilities
Accounts receivable, net	(1,961,000)	0
Inventory	(5,299,000)	0
Prepaid, current and other assets	955,000	1,718,000
Accounts payable, accrued expenses and other current liabilities	10,924,000	(1,981,000)
Net cash used in operating activities	(121,062,000)	(67,063,000)
Cash flows from investing activities
Purchase of available-for-sale investments	(56,195,000)	(101,217,000)
Proceeds from sales and maturities of investments	107,297,000	48,696,000
Purchase of property, plant and equipment	(29,404,000)	(7,073,000)
Net cash provided by (used in) investing activities	21,698,000	(59,594,000)
Cash flows from financing activities
Proceeds from sale of common stock, net	135,972,000	122,046,000
Proceeds related to issuance of stock for stock-based compensation arrangements, net	2,933,000	744,000
Payment of debt issuance costs	(1,621,000)	0
Other financing	(535,000)	0
Net cash provided by financing activities	136,749,000	122,790,000
Net change in cash and cash equivalents	37,385,000	(3,867,000)
Cash and cash equivalents, at beginning of period	197,569,000	197,945,000
Cash and cash equivalents, at end of period	234,954,000	194,078,000
Non-cash financing activities
Conversion of convertible notes to common stock	$ 148,078,000	$ 0