CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 39,885	$ 58,750
Marketable securities	11,044	17,420
Accounts receivable, net of allowance for doubtful accounts of $886 and $713 at June 30, 2016 and December 31, 2015, respectively	18,260	15,647
Deferred commissions	1,500	1,368
Other receivables	897	818
Prepaid expenses and other current assets	5,387	3,875
Total current assets	76,973	97,878
Property and equipment, net	43,619	44,410
Intangible assets, net	978	896
Other assets	1,126	711
Total assets	122,696	143,895
Current liabilities
Accounts payable	4,965	5,138
Accrued expenses and other current liabilities	14,697	20,394
Deferred revenue	57,291	55,741
Deferred government grant obligation	1,003	985
Current portion of capital lease and financing obligations	1,625	1,808
Current portion of long-term debt	20	18
Total current liabilities	79,601	84,084
Deferred revenue	8,340	7,597
Deferred government grant obligation	1,497	1,996
Other long-term liabilities	4,026	3,343
Capital lease and financing obligations	20,358	21,083
Long-term debt	53	73
Total liabilities	113,875	118,176
Stockholders’ equity
Preferred stock, $0.001 par value per share, 100,000,000 shares authorized, no shares issued and outstanding	0	0
Additional paid-in-capital	209,022	202,371
Accumulated deficit	(200,504)	(176,934)
Accumulated other comprehensive income	262	241
Total stockholders’ equity	8,821	25,719
Total liabilities and stockholders’ equity	122,696	143,895
Class A Common Stock
Stockholders’ equity
Common stock	30	29
Class B Common Stock
Stockholders’ equity
Common stock	$ 11	$ 12