Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 54,539	$ 73,933
Investments	138,704	131,149
Prepaid expenses and other current assets	5,126	2,528
Total current assets	198,369	207,610
Property and equipment, net	36,125	7,751
Long-term investments	36,752
Restricted cash	1,400	1,539
Total assets	272,646	216,900
Current liabilities:
Accounts payable	7,587	5,397
Accrued expenses and other current liabilities	10,812	5,523
Deferred revenue - related party	12,058
Total current liabilities	30,457	10,920
Lease incentive obligation, net of current portion	10,730	586
Deferred rent	2,072
Deferred revenue, net of current portion - related party	96,756
Total liabilities	140,015	11,506
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized at December 31, 2016 and 2015; no shares issued and outstanding at December 31, 2016 and 2015
Common stock, $0.001 par value; 200,000,000 shares authorized at December 31, 2016 and 2015; 40,355,753 and 39,082,017 shares issued and outstanding at December 31, 2016 and 2015	40	39
Additional paid-in capital	306,931	287,937
Accumulated other comprehensive income (loss)	(149)	30
Accumulated deficit	(174,191)	(82,612)
Total stockholders’ equity	132,631	205,394
Total liabilities, convertible preferred stock and stockholders’ equity	$ 272,646	$ 216,900