CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income	Non- Controlling Interest
Beginning Balances (in shares) at Dec. 31, 2019		115,972,708
Beginning Balances at Dec. 31, 2019	$ 432,739	$ 1,160	$ 1,090,828	$ (656,985)	$ (2,449)	$ 185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		24,420,157
Issuance of common stock in connection with at-the-market offering, net of offering expenses	142,526	$ 244	142,282
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax (in shares)		648,660
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax	2,468	$ 6	2,462
Issuance of common stock under employee stock purchase plan (in shares)		171,305
Issuance of common stock under employee stock purchase plan	1,187	$ 2	1,185
Stock-based compensation	19,066		19,066
Acquisition of additional shares of Sangamo France	(660)					(660)
Buy-out of non-controlling interest	0
Foreign currency translation adjustment	3,989				3,989
Net unrealized loss on marketable securities, net of tax	13				13
Net loss	(80,447)			(80,392)		(55)
Ending Balances (in shares) at Sep. 30, 2020		141,212,830
Ending Balances at Sep. 30, 2020	520,881	$ 1,412	1,255,823	(737,377)	1,553	(530)
Beginning Balances (in shares) at Jun. 30, 2020		140,973,277
Beginning Balances at Jun. 30, 2020	511,206	$ 1,410	1,247,527	(735,827)	(1,653)	(251)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax (in shares)		239,553
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax	1,616	$ 2	1,614
Stock-based compensation	6,682		6,682
Acquisition of additional shares of Sangamo France	(321)					(321)
Foreign currency translation adjustment	3,839				3,839
Net unrealized loss on marketable securities, net of tax	(633)				(633)
Net loss	(1,508)			(1,550)		42
Ending Balances (in shares) at Sep. 30, 2020		141,212,830
Ending Balances at Sep. 30, 2020	520,881	$ 1,412	1,255,823	(737,377)	1,553	(530)
Beginning Balances (in shares) at Dec. 31, 2020		142,063,203
Beginning Balances at Dec. 31, 2020	497,366	$ 1,421	1,269,375	(777,981)	5,419	(868)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		2,007,932
Issuance of common stock in connection with at-the-market offering, net of offering expenses	27,099	$ 20	27,079
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax (in shares)		1,200,871
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax	1,594	$ 12	1,582
Issuance of common stock under employee stock purchase plan (in shares)		244,570
Issuance of common stock under employee stock purchase plan	2,054	$ 2	2,052
Stock-based compensation	24,880		24,880
Acquisition of additional shares of Sangamo France	(134)		(70)			(64)
Buy-out of non-controlling interest	943		(943)			943
Foreign currency translation adjustment	(6,006)				(6,006)
Net unrealized loss on marketable securities, net of tax	(36)				(36)
Net loss	(140,801)			(140,790)		(11)
Ending Balances (in shares) at Sep. 30, 2021		145,516,576
Ending Balances at Sep. 30, 2021	406,016	$ 1,455	1,323,955	(918,771)	(623)	0
Beginning Balances (in shares) at Jun. 30, 2021		145,106,901
Beginning Balances at Jun. 30, 2021	445,457	$ 1,451	1,313,102	(871,083)	1,987	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)		202,705
Issuance of common stock in connection with at-the-market offering, net of offering expenses	2,367	$ 2	2,365
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax (in shares)		206,970
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, net of tax	617	$ 2	615
Stock-based compensation	7,873		7,873
Foreign currency translation adjustment	(2,565)				(2,565)
Net unrealized loss on marketable securities, net of tax	(45)				(45)
Net loss	(47,688)			(47,688)		0
Ending Balances (in shares) at Sep. 30, 2021		145,516,576
Ending Balances at Sep. 30, 2021	$ 406,016	$ 1,455	$ 1,323,955	$ (918,771)	$ (623)	$ 0