CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 50,576	$ 37,878
Short term investments	100,399	34,751
Accounts receivable	2,559	15,546
Prepaid expenses and other current assets	3,065	1,615
Total current assets	156,599	89,790
Property and equipment, net	4,597	4,034
Long term investments	700	9,922
Other non-current assets	129	130
Total assets	162,025	103,876
Current liabilities:
Accounts payable	3,174	2,452
Accrued expenses and other current liabilities	4,562	6,170
Deferred revenues, current portion	44,598	37,153
Total current liabilities	52,334	45,775
Deferred revenue, net of current portion	54,336	46,542
Other long-term liabilities	37	37
Total liabilities	106,707	92,354
Stockholders’ equity:
Preferred stock, $0.001 par value per share, 10,000,000 shares authorized and 2,907 and 4,963 issued and outstanding at June 30, 2018 and December 31, 2017	0	0
Common stock, $0.001 par value per share, 300,000,000 shares authorized and 54,008,056 and 45,017,062 issued and outstanding at June 30, 2018 and December 31, 2017	54	45
Additional paid-in capital	187,067	136,484
Accumulated other comprehensive loss	(2,574)	(4,695)
Accumulated deficit	(129,229)	(120,312)
Total stockholders’ equity	55,318	11,522
Total liabilities and stockholders’ equity	$ 162,025	$ 103,876