Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 22,061	$ 69,482
Marketable securities	120,474	139,518
Interest receivable	224	307
Accounts receivable	4,972	2,521
Prepaid expenses	1,849	754
Total current assets	149,580	212,582
Property and equipment, net	6,557	2,916
Goodwill	1,585	1,585
Other assets	169	152
Total assets	157,891	217,235
Current liabilities:
Accounts payable and accrued liabilities	6,261	8,229
Accrued compensation and employee benefits	2,885	2,748
Deferred revenues	4,145	9,120
Total current liabilities	13,291	20,097
Deferred revenues, non-current	4,460	4,699
Build-to-suit lease obligation	3,945
Total liabilities	21,696	24,796
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value; 160,000,000 shares authorized, 70,871,902 and 70,354,608 shares issued and outstanding at December 31, 2016 and December 31, 2015, respectively	709	703
Additional paid-in capital	576,377	560,989
Accumulated deficit	(440,911)	(369,253)
Accumulated other comprehensive income	20
Total stockholders' equity	136,195	192,439
Total liabilities and stockholders' equity	$ 157,891	$ 217,235