Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (294,090)	$ (254,337)	$ (324,277)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	9,147	5,188	3,577
Amortization of intangible assets	5,003	4,993	1,249
Stock-based compensation expense	36,158	26,971	26,240
Loss on extinguishment of debt	0	0	2,209
Amortization of debt issuance costs	1,397	1,397	1,350
Accretion of debt discount and back-end fee on debt	18,981	17,985	15,939
Noncash operating lease expense	1,078	360
Noncash operating lease expense	5,932	9,763
Changes in operating assets and liabilities:
Accounts receivable	2,670	(13,717)	(5,515)
Inventory	(21,180)	(21,281)	(7,032)
Prepaid expenses and other current assets	(3,114)	(8,718)	(5,514)
Other assets	(6,261)	(16,008)	0
Accounts payable	29,825	(4,966)	3,870
Accrued expenses and other	(10,675)	4,789	19,916
Accrued compensation	5,781	(3,068)	10,011
Net cash used in operating activities	(219,348)	(250,649)	(257,977)
Investing activities
Purchase of fixed assets	(6,240)	(42,268)	(13,090)
PARI milestone upon regulatory approvals	(582)	0	(1,724)
Net cash used in investing activities	(6,822)	(42,268)	(14,814)
Financing activities
Proceeds from issuance of 1.75% convertible senior notes due 2025	0	0	450,000
Payment of debt principal and extinguishment costs	0	0	(57,835)
Proceeds from issuance of common stock, net	245,866	261,074	0
Proceeds from exercise of stock options, ESPP, and RSU vesting	26,073	19,701	8,815
Payment of debt issuance costs	0	0	(14,237)
Financing cash flows for finance leases	(936)	0
Proceeds from tenant improvement allowance	0	4,503
Net cash provided by financing activities	271,003	285,278	386,743
Effect of exchange rates on cash and cash equivalents	494	(4)	(45)
Net increase (decrease) in cash and cash equivalents	45,327	(7,643)	113,907
Cash and cash equivalents at beginning of period	487,429	495,072	381,165
Cash and cash equivalents at end of period	532,756	487,429	495,072
Supplemental disclosures of cash flow information:
Cash paid for interest	9,186	7,883	6,289
Cash paid for income taxes	$ 814	$ 339	$ 154