Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net income	$ 126,198	$ 487,074
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,078	1,164
Loss on disposal of property and equipment		93
Share-based compensation expense	19,757	16,191
Change in fair value of note hedge warrants	(1,315)	(6,599)
Change in fair value of convertible note hedges	1,115	5,211
Non-cash interest expense	1,453	17,787
Deferred income taxes (including benefit from valuation allowance release)	45,610	(335,227)
Changes in assets and liabilities:
Accounts receivable, net	7,056	20,127
Prepaid expenses and other current assets	1,578	(1,032)
Operating lease right-of-use assets	985	910
Other assets	137	89
Accounts payable and accrued expenses	(6,108)	(6,710)
Accrued research and development costs	(10,223)	(223)
Operating lease liabilities	(1,474)	(1,359)
Other liabilities	8,734	(169)
Net cash provided by operating activities	194,581	197,327
Cash flows from investing activities:
Purchases of property and equipment	(163)	(137)
Net cash (used in) investing activities	(163)	(137)
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	6,734	14,037
Payment on 2022 Convertible Notes	(120,699)
Repurchases of common stock	(126,394)
Net cash provided by (used in) financing activities	(240,359)	14,037
Net increase in cash, cash equivalents and restricted cash	(45,941)	211,227
Cash, cash equivalents and restricted cash, beginning of period	621,864	364,784
Cash, cash equivalents and restricted cash, end of period	$ 575,923	$ 576,011