CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 332,798	$ 58,064
Short-term marketable securities	154,233	222,767
Receivables from collaborative arrangements	14,214	11,996
Receivables from licensing arrangements	1,200	10,000
Amounts due from TRC, LLC	26,282	28,574
Other prepaid and current assets	5,491	7,087
Total current assets	534,218	338,488
Property and equipment, net	13,905	12,644
Long-term marketable securities	5,067	4,985
Operating lease assets	46,106	46,604
Tax receivable	3,972	3,682
Restricted cash	833	833
Other assets	1,308	1,590
Total assets	605,409	408,826
Current liabilities:
Accounts payable	6,645	4,758
Accrued personnel-related expenses	24,708	28,180
Accrued clinical and development expenses	22,658	17,587
Accrued interest payable	6,323	5,659
Non-recourse notes due 2033, net		9,851
Operating lease liabilities	7,954	7,762
Deferred revenue	23,193	31,575
Other accrued liabilities	6,559	6,331
Total current liabilities	98,040	111,703
Convertible senior notes due 2023, net	226,158	225,890
Non-recourse notes due 2035, net	373,854
Non-recourse notes due 2033, net		219,300
Long-term operating lease liabilities	47,199	47,725
Long-term deferred revenue	8,511	6,761
Other long-term liabilities	9,583	21,287
Commitments and contingencies
Shareholders' Deficit
Preferred shares, $0.00001 par value: 230 shares authorized, no shares issued or outstanding	0	0
Ordinary shares, $0.00001 par value: 200,000 shares authorized; 63,004 and 57,015 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	1	1
Additional paid-in capital	1,173,204	1,024,614
Accumulated other comprehensive income	512	145
Accumulated deficit	(1,331,653)	(1,248,600)
Total shareholders' deficit	(157,936)	(223,840)
Total liabilities and shareholders' deficit	$ 605,409	$ 408,826