Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net loss	$ (199,581)	$ (232,569)	$ (145,105)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	5,138	2,442	1,410
Amortization and accretion	12,976	1,646	315
Acquisition of assets expensed to research and development	10,171	0	24,802
Stock-based compensation	45,093	38,728	26,078
Induced conversion of 2014 Convertible Notes	0	24,059	0
Other non-cash	(271)	(270)	601
Changes in operating assets and liabilities
Accounts receivable, net	(35,639)	(2,715)	0
Inventory	(10,257)	(9,689)	0
Prepaid, current and other assets	(2,144)	(791)	(2,239)
Accounts payable, accrued expenses and other current liabilities	28,766	26,583	925
Operating lease liabilities	(4,682)
Net cash used in operating activities	(150,430)	(152,576)	(93,213)
Cash flows from investing activities
Acquisition of assets	(7,835)	0	(10,500)
Purchase of available-for-sale investments	(165,454)	(56,195)	(104,490)
Proceeds from sales and maturities of investments	0	108,297	88,153
Purchase of property, plant and equipment	(9,958)	(31,313)	(15,970)
Net cash (used in) provided by investing activities	(183,247)	20,789	(42,807)
Cash flows from financing activities
Proceeds from sale of common stock, net	0	135,972	134,215
Proceeds related to issuance of stock for stock-based compensation arrangements, net	684	3,630	1,429
Proceeds from exercise of warrants	761	0	0
Proceeds from convertible notes, net of issuance costs	308,349	0	0
Payments of issuance costs	(1,769)	(1,883)	0
Payment for capped call options	(32,890)	0	0
Other financing	(336)	(683)	0
Net cash provided by financing activities	274,799	137,036	135,644
Net change in cash and cash equivalents	(58,878)	5,249	(376)
Cash and cash equivalents, at beginning of period	202,818	197,569	197,945
Cash and cash equivalents, at end of period	143,940	202,818	197,569
Supplemental disclosures
Cash paid for interest	6,496	1,774	2,188
Non-cash investing and financing activities:
Conversion of convertible notes to common stock (Note 10)	0	148,078	0
Equity issued for Envisia Asset Acquisition	0	0	14,302
Liabilities incurred from Avizorex Asset Acquisition	1,186	0	0
Purchases of property, plant and equipment in accounts payable and accrued expense and other current liabilities	771	3,526	4,176
Acquisition of capital lease obligation	0	0	689
Deferred costs from the sale of common stock	0	0	403
Build-to-suit lease transaction (Note 7)