Condensed Consolidated Statements of Cash Flows $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Cash flows from operating activities:
Net loss	$ (248,655)	$ (168,312)
Adjustments to reconcile net loss to cash flows from operating activities:
Gain from sale of Priority Review Voucher, net of commission	(102,000)	(108,069)
Depreciation and amortization	17,377	13,004
Reduction in the carrying amounts of the right of use assets	6,023	5,389
Amortization of investment discount	(101)	(1,928)
Non-cash interest expense	3,691	12,217
Stock-based compensation	57,477	51,640
Other	3,786	(800)
Changes in operating assets and liabilities, net:
Net increase in accounts receivable	(26,180)	(13,149)
Net increase in inventory	(36,795)	(8,271)
Net decrease (increase) in other assets	73,670	(44,309)
Net (decrease) increase in deferred revenue	(44,255)	794,484
Net increase (decrease) in accounts payable, accrued expenses and other liabilities	6,445	(11,709)
Net cash (used in) provided by operating activities	(289,517)	520,187
Cash flows from investing activities:
Purchase of property and equipment	(27,043)	(28,289)
Proceeds from sale of Priority Review Voucher, net of commission	102,000	108,069
Purchase of available-for-sale securities	(29,989)	(756,738)
Maturity and sale of available-for-sale securities	436,000	626,980
Other	(3,243)	(1,927)
Net cash provided by (used in) investing activities	477,725	(51,905)
Cash flows from financing activities:
Proceeds from exercise of stock options and purchase of stock under the Employee Stock Purchase Program	12,752	29,342
Taxes paid related to net share settlement of equity awards	(6,333)	(4,798)
Net cash provided by financing activities	6,419	336,597
Increase in cash, cash equivalents and restricted cash	194,627	804,879
Cash, cash equivalents and restricted cash:
Beginning of period	1,511,713	843,645
End of period	1,706,340	1,648,524
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	1,697,275	1,639,959
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	$ 1,706,340	$ 1,648,524
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	27,780	15,032
Supplemental schedule of non-cash investing activities and financing activities:
Intangible assets and property and equipment included in accounts payable and accrued expenses	7,760	9,032
Shares withheld for tax included in accrued expenses	1,432
Lease liabilities arising from obtaining right of use assets	10,582	37,586
Lease liabilities terminated	$ 19,967
Roche
Cash flows from financing activities:
Proceeds from issuance of common stock to Roche, net of offering costs		$ 312,053