Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 53,470	$ 55,912
Marketable securities	117,421	164,195
Accounts receivable	4,129	1,480
Prepaid expenses and other current assets	19,077	23,011
Research and development tax credit receivable	11,226	30,723
Total current assets	205,323	275,321
Operating lease right-of-use-assets	25,455	24,316
Property and equipment, net	5,733	4,767
Restricted cash	4,266	4,266
Intangible assets, net	3,736	4,149
Research and development tax credit receivable	3,950
Other assets	10,696	9,590
Total assets	259,159	322,409
Current liabilities:
Accounts payable	8,802	10,008
Accrued expenses and other current liabilities	26,286	24,318
Deferred revenue, current	1,147	346
Operating lease liabilities	6,670	7,335
Notes payable, current	5,500	786
Total current liabilities	48,405	42,793
Notes payable, long-term	27,539	32,086
Deferred revenue, net of current portion	10,291	12,519
Operating lease liabilities, net of current portion	20,183	19,278
Other long-term liabilities	6,469	5,783
Total liabilities	112,887	112,459
Commitments and contingencies (see Note 13)
Shareholders’ equity:
Ordinary shares, GBP0.10 par value, authority to allot up to a maximum nominal value of GBP13,023,851.50 of shares at June 30, 2022 and December 31, 2021, respectively; 126,436,213 and 125,674,095 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively.	16,353	16,253
Additional paid-in capital	949,325	940,675
Accumulated other comprehensive income	26,030	3,246
Accumulated deficit	(845,436)	(750,224)
Total shareholders’ equity	146,272	209,950
Total liabilities and shareholders’ equity	$ 259,159	$ 322,409