Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	[1]
Current assets:
Cash and cash equivalents	$ 280,379	$ 175,126
Short-term investments	619,271	355,407
Prepaid expenses and other current assets	9,927	14,043
Total current assets	909,577	544,576
Long-term investments	210,794	58,322
Operating lease right-of-use asset	42,432	44,495
Property and equipment, net	84,605	56,449
Intangible assets, net	0	151
Restricted cash	4,299	4,299
Other long-term assets	2,160	4,618
Equity method investment	4,677	4,892
Total assets	1,258,544	717,802
Current liabilities:
Accounts payable	9,057	9,250
Accrued and other current liabilities	31,838	23,829
Total current liabilities	40,895	33,079
Lease liability, noncurrent	51,067	51,349
Other long-term liabilities	3,163	4,351
Total liabilities	95,125	88,779
Commitments and Contingencies (Notes 6 and 7)
Stockholders’ equity:
Preferred stock, $0.001 par value: 10,000,000 shares authorized as of June 30, 2020 and December 31, 2019; no shares were issued and outstanding as of June 30, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value: 200,000,000 shares authorized as of June 30, 2020 and December 31, 2019; 139,233,450 and 124,267,358 shares issued and outstanding as of June 30, 2020 and December 31, 2019, respectively	139	124
Additional paid-in capital	1,673,026	1,023,876
Accumulated deficit	(511,576)	(396,122)
Accumulated other comprehensive income	1,830	1,145
Total stockholders’ equity	1,163,419	629,023
Total liabilities and stockholders’ equity	$ 1,258,544	$ 717,802

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