CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (83,053)	$ (72,580)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,424	1,316
Amortization and accretion income, net	(536)	(629)
Share-based compensation	15,276	12,220
Amortization of right-of-use assets	457	986
Amounts due from TRC, LLC	2,295	(6,229)
Loss on extinguishment of debt	15,464
Other	9	16
Changes in operating assets and liabilities:
Accounts receivable		507
Receivables from collaborative and licensing arrangements	6,582	2,229
Other prepaid and current assets	1,592	(2,135)
Other assets	(99)
Accounts payable	1,154	(3,440)
Accrued personnel-related expenses, accrued clinical and development expenses, and other accrued liabilities	(10,549)	(2,703)
Accrued interest payable	664	(4,581)
Deferred revenue	(6,632)	(5,333)
Operating lease liabilities	(293)	(910)
Other long-term liabilities	144	73
Net cash used in operating activities	(55,101)	(81,193)
Investing activities
Purchases of property and equipment	(954)	(1,220)
Purchases of marketable securities	(64,778)	(148,138)
Maturities of marketable securities	119,203	77,198
Proceeds from the sale of marketable securities	14,932
Net cash provided by (used in) investing activities	68,403	(72,160)
Financing activities
Proceeds from the sale of ordinary shares, net	139,915
Proceeds from issuance of 2035 notes, net	380,000
Payment of issuance costs on 2035 notes	(5,065)
Payment of redemption premium on 2033 notes	(11,470)
Principal payment on 2033 notes	(235,347)
Proceeds from option exercises	203	254
Repurchase of shares to satisfy tax withholding	(6,804)	(1,687)
Net cash provided by (used in) financing activities	261,432	(1,433)
Net increase (decrease) in cash, cash equivalents, and restricted cash	274,734	(154,786)
Cash, cash equivalents, and restricted cash at beginning of period	58,897
Cash, cash equivalents, and restricted cash at end of period	333,631	224,068
Supplemental disclosure of cash flow information
Cash paid for interest	7,891
Cash paid (received) for income taxes, net	$ (9)
Right-of-use assets obtained in exchange for lease obligations (1)		$ 49,847