Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 77,205	$ 32,297
Short-term investments	235,399	404,273
Accounts receivable, other	118	137
Accounts receivable from related party	53	32
Prepaid expenses and other current assets	4,358	4,831
Total current assets	317,133	441,570
Property and equipment, net	33,781	25,160
Long-term investments	90,028	23,800
Operating lease right-of-use assets	25,291	26,911
Other assets	1,439	1,458
Total assets	467,672	518,899
Current liabilities:
Accounts payable	11,094	12,875
Accrued and other current liabilities	20,686	19,794
Long-term debt, current	12,984	6,302
Deferred revenue from related party	10,615	12,587
Total current liabilities	55,379	51,558
Long-term debt, net	11,566	18,099
Non-current deferred revenue from related party	24,108	24,000
Non-current lease liabilities	45,179	38,671
Other non-current liabilities	1,170	958
Total liabilities	137,402	133,286
Commitments (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value, 200,000,000 shares authorized; 69,885,975 and 69,452,466 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	70	69
Additional paid-in capital	884,559	870,788
Note receivable	(16)	(16)
Accumulated other comprehensive income (loss)	(81)	114
Accumulated deficit	(554,262)	(485,342)
Total stockholders’ equity	330,270	385,613
Total liabilities and stockholders’ equity	$ 467,672	$ 518,899