CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 199,693	$ 83,966
Short-term investments	37,568	225,186
Prepaid expenses and other current assets	3,111	4,844
Total current assets	240,372	313,996
Property and equipment, net	23,296	23,336
Operating lease right-of-use assets	26,069	24,986
Intangible assets	1,320	1,320
Goodwill	4,228	4,228
Other long-term assets	3,826	3,618
Total assets	299,111	371,484
Current liabilities:
Accounts payable	4,506	763
Accrued expenses and other liabilities	21,852	24,454
Operating lease liabilities, current	5,641	4,808
Total current liabilities	31,999	30,025
Operating lease liabilities, non-current	26,086	25,374
Term debt	29,273	29,133
Deferred CIRM grant liability	23,755	23,755
Deferred tax liability	55	55
Other long-term liabilities	1,367	1,174
Total liabilities	112,535	109,516
Commitments and Contingencies (Note 10)
Stockholders’ equity:
Common stock, $0.0001 par value: 250,000,000 shares authorized at June 30, 2021 and December 31, 2020; 62,166,167 and 61,860,897 shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively	6	6
Additional paid-in capital	552,473	543,842
Accumulated other comprehensive income	1	5
Accumulated deficit	(365,904)	(281,885)
Total stockholders’ equity	186,576	261,968
Total liabilities and stockholders’ equity	$ 299,111	$ 371,484