Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	[1]
Current assets:
Cash and cash equivalents	$ 158,136	$ 175,126
Short-term investments	682,886	355,407
Prepaid expenses and other current assets	13,036	14,043
Total current assets	854,058	544,576
Long-term investments	207,993	58,322
Operating lease right-of-use asset	41,557	44,495
Property and equipment, net	102,653	56,449
Intangible assets, net	0	151
Restricted cash	9,449	4,299
Other long-term assets	2,274	4,618
Equity method investment	4,516	4,892
Total assets	1,222,500	717,802
Current liabilities:
Accounts payable	10,151	9,250
Accrued and other current liabilities	39,979	23,829
Total current liabilities	50,130	33,079
Lease liability, noncurrent	50,846	51,349
Other long-term liabilities	2,793	4,351
Total liabilities	103,769	88,779
Commitments and Contingencies (Notes 6 and 7)
Stockholders’ equity:
Preferred stock, $0.001 par value: 10,000,000 shares authorized as of September 30, 2020 and December 31, 2019; no shares were issued and outstanding as of September 30, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value: 200,000,000 shares authorized as of September 30, 2020 and December 31, 2019; 139,755,839 and 124,267,358 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively	140	124
Additional paid-in capital	1,695,411	1,023,876
Accumulated deficit	(577,773)	(396,122)
Accumulated other comprehensive income	953	1,145
Total stockholders’ equity	1,118,731	629,023
Total liabilities and stockholders’ equity	$ 1,222,500	$ 717,802

[1] The balance sheet as of December 31, 2019 is derived from the audited financial statements as of that date.