Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 166,422	$ 254,712
Short-term investments, available for sale	342,318	261,217
Accounts receivable	42,646	31,127
Other current assets	16,291	7,863
Total current assets	567,677	554,919
Property and equipment, net	18,775	10,811
Long-term investments, available for sale	249,388	247,361
Restricted cash	5,477	4,500
Total assets	841,317	817,591
Current liabilities:
Accounts payable and accrued liabilities	61,031	53,520
Other current liabilities	731	906
Total current liabilities	61,762	54,426
Deferred gain on sale of real estate	7,677	8,043
Deferred revenue	10,231	10,231
Deferred rent	5,326	3,135
Convertible senior notes	378,885	369,618
Total liabilities	463,881	445,453
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value; 220,000,000 shares authorized; issued and outstanding shares were 90,403,238 as of June 30, 2018 and 88,793,903 as of December 31, 2017	90	89
Additional paid-in capital	1,626,752	1,572,765
Accumulated other comprehensive loss	(2,809)	(1,850)
Accumulated deficit	(1,246,597)	(1,198,866)
Total stockholders’ equity	377,436	372,138
Total liabilities and stockholders’ equity	$ 841,317	$ 817,591