Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 179,432	$ 173,415
Short-term investments	345,210	555,231
Receivable from collaboration partners ($617 and $943 from a related party)	871	1,049
Accrued interest receivable	2,201	649
Prepaid expenses and other current assets	17,574	5,471
Total current assets	545,288	735,815
Long-term investments	218,730	6,440
Property and equipment, net	28,818	10,807
Right-of-use assets	35,553	12,781
Restricted cash	3,005	203
Other long-term assets	7,896	6,246
Total assets	839,290	772,292
Current liabilities:
Accounts payable	13,219	15,682
Accrued research and development	40,470	18,307
Other accrued liabilities	14,625	9,543
Deferred revenue, current ($67,571 and $67,571 to a related party)	74,343	74,571
Other current liabilities	209	3,566
Total current liabilities	142,866	121,669
Deferred revenue, noncurrent ($94,675 and $117,808 to a related party)	94,675	122,830
Operating lease liabilities, noncurrent	48,943	15,243
Other long-term liabilities ($9,703 and $9,703 to a related party)	10,199	10,246
Total liabilities	296,683	269,988
Commitments (Note 11)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of September 30, 2021 and December 31, 2020; no shares issued and outstanding as of September 30, 2021 and December 31, 2020	0	0
Common stock, $0.0001 par value, 400,000,000 shares authorized as of September 30, 2021 and December 31, 2020; 70,241,590 and 65,114,685 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively. Shares outstanding includes 39,142 and 1,422,784 shares issued but subject to vesting as of September 30, 2021 and December 31, 2020, respectively	7	6
Additional paid-in capital	1,097,414	830,438
Accumulated deficit	(554,722)	(328,184)
Accumulated other comprehensive (loss) income	(92)	44
Total stockholders’ equity	542,607	502,304
Total liabilities and stockholders’ equity	$ 839,290	$ 772,292