CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net loss	$ (192,278)	$ (178,297)	$ (121,122)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	12,108	9,439	5,682
Amortization of (discount) premium on marketable securities	(1,242)	2,844	(825)
Amortization and other changes in operating lease right-of-use assets	8,454	8,199	7,687
Stock-based compensation	31,650	32,956	25,708
Gain on free shares	0	(18)	(63)
Net (gain) loss on disposal of property and equipment	0	(52)	222
Adjustment of CIRM award liability related to termination of the grant	0	(6,427)	0
Net changes in operating assets and liabilities:
Interest receivable	(445)	686	(353)
Accounts receivable	2,335	(789)	31,685
Prepaid expenses and other assets	(4,909)	(7,175)	(10,411)
Accounts payable and other accrued liabilities	13,348	(7,664)	10,703
Accrued compensation and employee benefits	941	373	6,877
Deferred revenues	(91,331)	(84,202)	216,546
Lease liabilities	(2,249)	(4,340)	(3,761)
Other non-current liabilities	(9)	1,216	1,300
Net cash (used in) provided by operating activities	(223,627)	(233,251)	169,875
Investing Activities:
Purchases of marketable securities	(277,391)	(338,159)	(570,779)
Maturities of marketable securities	354,587	602,885	314,570
Sales of marketable securities	2,260	6,870	0
Purchases of property and equipment	(20,171)	(23,278)	(14,714)
Purchase of additional Sangamo France shares	0	(119)	(704)
Net cash provided by (used in) investing activities	59,285	248,199	(271,627)
Financing Activities:
Taxes paid related to net share settlement of equity awards	(2,104)	(3,258)	(765)
Proceeds from exercise of stock options	124	5,648	9,324
Net cash provided by financing activities	84,660	32,858	153,100
Effect of exchange rate changes on cash and cash equivalents, and restricted cash	1,254	(263)	(447)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(78,428)	47,543	50,901
Cash, cash equivalents, and restricted cash, beginning of period	180,372	132,829	81,928
Cash, cash equivalents, and restricted cash, end of period	101,944	180,372	132,829
Supplemental cash flow disclosures:
Property and equipment included in unpaid liabilities	6,539	1,535	4,569
Tenant improvement allowance included in contra-lease liability	243	0	0
Buy-out of non-controlling interest	0	943	0
Right-of-use assets obtained in exchange for lease obligations	0	10,418	1,333
At -the-market offering
Financing Activities:
Proceeds from issuance of common stock	84,869	27,099	0
Biogen Collaboration Agreement
Financing Activities:
Proceeds from issuance of common stock	0	0	142,526
Employee Stock
Financing Activities:
Proceeds from issuance of common stock	$ 1,771	$ 3,369	$ 2,015