Discontinued operations - Assets, Liabilities and Stockholders' Equity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Nov. 04, 2021	Dec. 31, 2020
Current assets:
Total current assets of discontinued operations	$ 0		$ 495,021
Non-current assets of discontinued operations	0		343,564
Current liabilities:
Total current liabilities	0		81,876
Non-current liabilities of discontinued operations	$ 0		161,142
2seventy bio | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Current assets:
Cash and cash equivalents		$ 174,284	57,076
Marketable securities		160,447	413,947
Prepaid expenses		8,732	11,754
Receivables and other current assets		21,637	12,244
Total current assets of discontinued operations		365,100	495,021
Marketable securities		106,826	61,446
Property, plant and equipment, net		33,972	145,458
Intangible assets, net		10,664	5,644
Goodwill		6,410	7,482
Operating lease right-of-use assets		255,556	116,456
Restricted cash and other non-current assets		5,650	7,078
Non-current assets of discontinued operations			343,564
Total assets		784,178	838,585
Current liabilities:
Accounts payable		2,982	7,791
Accrued expenses and other current liabilities		85,659	48,716
Operating lease liability, current portion		6,938	15,313
Collaboration research advancement, current portion		8,957	9,236
Deferred revenue, current portion			820
Total current liabilities		104,536	81,876
Deferred revenue, net of current portion		25,762	25,762
Collaboration research advancement, net of current portion		16,264	21,581
Operating lease liability, net of current portion		257,575	112,290
Other non-current liabilities		1,896	1,509
Non-current liabilities of discontinued operations			161,142
Total liabilities		406,033	$ 243,018
Net assets transferred to 2seventy bio		$ 378,145