Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	[1]
Current assets:
Cash and cash equivalents	$ 135,897	$ 175,126
Short-term investments	357,026	355,407
Prepaid expenses and other current assets	11,491	14,043
Total current assets	504,414	544,576
Long-term investments	60,121	58,322
Operating lease right-of-use asset	43,836	44,495
Property and equipment, net	66,349	56,449
Intangible assets, net	0	151
Restricted cash	4,299	4,299
Other long-term assets	4,675	4,618
Equity method investment	4,829	4,892
Total assets	688,523	717,802
Current liabilities:
Accounts payable	7,199	9,250
Accrued and other current liabilities	19,619	23,829
Total current liabilities	26,818	33,079
Lease liability, noncurrent	51,536	51,349
Other long-term liabilities	3,650	4,351
Total liabilities	82,004	88,779
Commitments and Contingencies (Notes 6 and 7)
Stockholders’ equity:
Preferred stock, $0.001 par value: 10,000,000 shares authorized as of March 31, 2020 and December 31, 2019; no shares were issued and outstanding as of March 31, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value: 200,000,000 shares authorized as of March 31, 2020 and December 31, 2019; 125,262,537 and 124,267,358 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	125	124
Additional paid-in capital	1,055,386	1,023,876
Accumulated deficit	(450,602)	(396,122)
Accumulated other comprehensive income	1,610	1,145
Total stockholders’ equity	606,519	629,023
Total liabilities and stockholders’ equity	$ 688,523	$ 717,802

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