CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating Activities:
Net loss	$ (78,939)	$ (72,559)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	2,639	1,583
Amortization of discount on marketable securities	(1,146)	(2,455)
Amortization and other changes in right-of-use assets	3,788	1,923
Gain on free shares	(48)	(551)
Stock-based compensation	12,384	9,390
Net loss on lease termination	0	218
Other	0	11
Net changes in operating assets and liabilities:
Interest receivable	148	(391)
Accounts receivable	31,291	(7,422)
Prepaid expenses and other assets	(7,763)	(5,449)
Accounts payable and accrued liabilities	1,559	1,811
Accrued compensation and employee benefits	(248)	(764)
Deferred revenues	178,890	(10,821)
Long-term portion of lease liabilities	(1,797)	(563)
Other non-current liabilities	345	1,327
Net cash provided by (used in) operating activities	141,103	(84,712)
Investing Activities:
Purchases of marketable securities	(43,580)	(244,306)
Maturities of marketable securities	151,839	226,884
Purchases of property and equipment	(6,694)	(9,760)
Purchase of additional shares of Sangamo France	(237)	0
Net cash provided by (used in) investing activities	101,328	(27,182)
Financing Activities:
Proceeds from public offering of common stock, net of issuance costs	0	136,308
Proceeds from issuance of common stock in connection with the Biogen collaboration agreement, net of issuance costs	142,526	0
Taxes paid related to net share settlement of equity awards	(455)	(296)
Proceeds from exercise of stock options and restricted stock units	1,307	4,094
Proceeds from exercise of stock options and restricted stock units	1,187	0
Net cash provided by financing activities	144,565	140,106
Effects of changes in foreign exchange rates	19	592
Net increase in cash, cash equivalents, and restricted cash	387,015	28,804
Cash, cash equivalents, and restricted cash, beginning of period	81,928	143,918
Cash, cash equivalents, and restricted cash, end of period	468,943	172,722
Supplemental disclosure of non-cash activities:
Property and equipment included in unpaid liabilities	1,977	1,679
Right-of-use assets obtained in exchange for lease obligations	$ 0	$ 29,671