Significant Accounting Policies - Cumulative effect of changes to consolidated Balance Sheet for the Adoption of ASC 606 (Table) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Trade accounts receivable	$ 24,708	$ 18,521
Other current assets	5,638	5,157
Liabilities
Deferred revenue	6,523	7,229
Accrued liabilities	11,475	10,521
Stockholders' Equity
Accumulated deficit	(1,017,532)	(1,036,303)
Cumulative effect of the adoption of ASC 606 on the opening consolidated balance sheet
Assets
Trade accounts receivable		16,138
Other current assets		6,817
Liabilities
Deferred revenue		8,366
Accrued liabilities		10,518
Stockholders' Equity
Accumulated deficit		(1,038,160)
Effect of Adoption of ASC 606
Assets
Trade accounts receivable	(2,504)	(2,383)
Other current assets	2,540	1,660
Liabilities
Deferred revenue	(1,292)	(1,137)
Accrued liabilities	$ 20	3
Stockholders' Equity
Accumulated deficit		$ (1,857)

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.

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-Name Accounting Standards Codification
-Topic 606
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-Section 50
-Paragraph 8
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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. 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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