Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 278,887	$ 164,269
Marketable securities	425,491	353,680
Prepaid expenses and other current assets	19,836	6,016
Total current assets	724,214	523,965
Marketable securities	180,452	347,814
Property and equipment, net	156,955	82,614
Intangible assets, net	20,694	24,456
Goodwill	13,128	13,128
Restricted cash and other non-current assets	22,679	10,360
Total assets	1,118,122	1,002,337
Current liabilities:
Accounts payable	13,664	6,334
Accrued expenses and other current liabilities	54,660	28,145
Deferred revenue, current portion	6,209	5,889
Total current liabilities	74,533	40,368
Deferred rent, net of current portion	10,408	8,294
Deferred revenue, net of current portion	40,204	35,959
Contingent consideration, net of current portion	3,277	5,082
Construction financing lease obligation	120,140	61,901
Other non-current liabilities	120	237
Total liabilities	248,682	151,841
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at December 31, 2016 and December 31, 2015
Common stock, $0.01 par value, 125,000 shares authorized; 40,691 and 36,894 shares issued and outstanding at December 31, 2016 and December 31, 2015, respectively	407	369
Additional paid-in capital	1,447,856	1,166,585
Accumulated other comprehensive loss	(1,149)	(2,291)
Accumulated deficit	(577,674)	(314,167)
Total stockholders' equity	869,440	850,496
Total liabilities and stockholders' equity	$ 1,118,122	$ 1,002,337