Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 57,937	$ 71,064
Short-term investments	130,333	185,480
Receivable from collaboration partner	132
Prepaid expenses and other current assets	4,303	2,321
Amounts owed by a related party		83
Total current assets	192,705	258,948
Long-term investments		3,181
Property and equipment, net	9,330	11,107
Equity investment in related party		1,202
Restricted cash	203	203
Other long-term assets	872	284
Total assets	203,110	274,925
Current liabilities:
Accounts payable	4,704	3,102
Accrued liabilities	9,522	6,023
Deferred revenue, current	7,000	6,250
Other current liabilities	1,480	1,560
Total current liabilities	22,706	16,935
Deferred revenue, noncurrent	12,022	16,984
Deferred rent	3,734	4,272
Other long-term liabilities	806	1,792
Total liabilities	39,268	39,983
Commitments (Note 11)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of December 31, 2019 and 2018; no shares issued and outstanding as of December 31, 2019 and 2018	0	0
Common stock, $0.0001 par value, 400,000,000 shares authorized as of December 31, 2019 and 2018; 45,925,004 and 44,537,946 shares issued and outstanding as of December 31, 2019 and 2018, respectively	4	4
Additional paid-in capital	369,100	357,873
Accumulated deficit	(205,326)	(122,828)
Accumulated other comprehensive income (loss)	64	(107)
Total stockholders’ equity	163,842	234,942
Total liabilities and stockholders’ equity	$ 203,110	$ 274,925