CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 65,256	$ 60,333
Marketable securities	15,801	16,364
Accounts receivable, net of allowance for doubtful accounts of $451 and $388 at March 31, 2018 and December 31, 2017, respectively	39,202	28,800
Deferred commissions	3,845	2,376
Other receivables	949	975
Prepaid expenses	6,216	6,444
Total current assets	131,269	115,292
Property and equipment, net	39,801	40,444
Deferred commissions, non-current	5,489	0
Intangible assets, net	1,158	1,118
Other assets	920	861
Total assets	178,637	157,715
Current liabilities
Accounts payable	5,913	3,060
Accrued expenses and other current liabilities	26,383	20,212
Deferred revenue	110,943	104,684
Deferred government grant obligation	129	217
Current portion of capital lease and financing obligations	1,161	1,168
Total current liabilities	144,529	129,341
Deferred revenue, non-current	20,968	22,709
Deferred government grant obligation	258	278
Other long-term liabilities	3,966	3,896
Capital lease and financing obligations	18,134	18,425
Total liabilities	187,855	174,649
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	257,297	248,289
Accumulated deficit	(266,574)	(265,337)
Accumulated other comprehensive income	16	72
Total stockholders’ deficit	(9,218)	(16,934)
Total liabilities and stockholders’ deficit	178,637	157,715
Class A Common Stock
Stockholders’ deficit
Common stock	33	32
Class B Common Stock
Stockholders’ deficit
Common stock	$ 10	$ 10

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.