Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (167,250)	$ (17,492)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation and amortization	8,930	6,529
Reduction in the carrying amounts of the right of use assets	2,220	2,153
Amortization of investment discount	(82)	(1,284)
Non-cash interest expense	1,816	6,342
Stock-based compensation	28,508	24,024
Gain from sale of Priority Review Voucher, net of commission		(108,069)
Other	2,774	(1,381)
Changes in operating assets and liabilities, net:
Net increase in accounts receivable	(16,863)	(15,996)
Net increase in inventory	(8,372)	(1,789)
Net decrease (increase) in other assets	(34,915)	27,966
Net (decrease) increase in deferred revenue	(22,005)	820,437
Net decrease in accounts payable, accrued expenses and other liabilities	(44,962)	(57,718)
Net cash (used in) provided by operating activities	(180,371)	627,790
Cash flows from investing activities:
Purchase of property and equipment	(21,149)	(9,120)
Purchase of available-for-sale securities	(29,989)	(365,437)
Maturity and sale of available-for-sale securities	210,000	250,000
Proceeds from sale of Priority Review Voucher, net of commission		108,069
Other	(2,196)	(1,192)
Net cash provided by (used in) investing activities	156,666	(17,680)
Cash flows from financing activities:
Proceeds from exercise of stock options and purchase of stock under the Employee Stock Purchase Program	9,226	7,482
Taxes paid related to net share settlement of equity awards	(6,333)	(4,798)
Net cash provided by financing activities	2,893	319,022
(Decrease) increase in cash, cash equivalents and restricted cash	(20,812)	929,132
Cash, cash equivalents and restricted cash:
Beginning of period	1,511,713	843,645
End of period	1,490,901	1,772,777
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	1,481,836	1,764,212
Restricted cash in other assets	$ 9,065	$ 8,565
Restricted Cash, Noncurrent, Asset, Statement of Financial Position [Extensible List]	Other non-current assets	Other non-current assets
Total cash, cash equivalents and restricted cash	$ 1,490,901	$ 1,772,777
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	11,688	5,385
Supplemental schedule of non-cash investing activities and financing activities:
Intangible assets and property and equipment included in accrued expenses	5,729	6,154
Lease liabilities arising from obtaining right of use assets	901	24,783
Lease liabilities terminated	$ 19,967
Issuance costs related to the Roche Collaboration in accrued expenses		4,285
Roche
Cash flows from financing activities:
Proceeds from issuance of common stock to Roche, net of offering costs		$ 316,338