Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 193,228	$ 73,933
Investments	110,050	131,149
Prepaid expenses and other current assets	3,568	2,528
Total current assets	306,846	207,610
Property and equipment, net	16,082	7,751
Restricted cash	1,540	1,539
Total assets	324,468	216,900
Current liabilities:
Accounts payable	5,763	5,397
Accrued expenses and other current liabilities	7,059	5,523
Deferred revenue - related party	12,000
Total current liabilities	24,822	10,920
Lease incentive obligation	4,527	586
Deferred revenue, net of current portion - related party	105,290
Total liabilities	$ 134,639	$ 11,506
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.001 par value; 200,000,000 shares authorized at March 31, 2016 and December 31, 2015; 39,218,702 and 39,082,017 shares issued and outstanding at March 31, 2016 and December 31, 2015 , respectively	$ 39	$ 39
Additional paid-in capital	291,998	287,937
Accumulated other comprehensive income	108	30
Accumulated deficit	(102,316)	(82,612)
Total stockholders’ equity	189,829	205,394
Total liabilities and stockholders’ equity	$ 324,468	$ 216,900