CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 62,718	$ 51,281
Marketable securities	15,033	11,435
Accounts receivable, net of allowance for doubtful accounts of $646 and $900 at September 30, 2017 and December 31, 2016, respectively	24,283	22,535
Deferred commissions	2,208	1,864
Other receivables	1,109	1,545
Prepaid expenses	6,298	9,382
Total current assets	111,649	98,042
Property and equipment, net	41,300	42,590
Intangible assets, net	1,088	1,012
Other assets	1,553	1,499
Total assets	155,590	143,143
Current liabilities
Accounts payable	1,861	849
Accrued expenses and other current liabilities	20,771	20,695
Deferred revenue	99,149	76,016
Deferred government grant obligation	813	1,022
Current portion of capital lease and financing obligations	1,184	1,285
Current portion of long-term debt	0	20
Total current liabilities	123,778	99,887
Deferred revenue	23,278	21,485
Deferred government grant obligation	289	1,000
Other long-term liabilities	4,008	4,100
Capital lease and financing obligations	18,709	19,743
Long-term debt	0	53
Total liabilities	170,062	146,268
Stockholders’ deficit
Preferred stock, $0.001 par value per share, 100,000,000 shares authorized, no shares issued and outstanding	0	0
Additional paid-in-capital	236,386	217,454
Accumulated deficit	(251,016)	(220,911)
Accumulated other comprehensive income	116	291
Total stockholders’ deficit	(14,472)	(3,125)
Total liabilities and stockholders’ deficit	155,590	143,143
Class A Common Stock
Stockholders’ deficit
Common stock	31	30
Class B Common Stock
Stockholders’ deficit
Common stock	$ 11	$ 11

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.