Other current assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other current assets [Abstract]
Due from equipment sales	$ 841	$ 2,197
Income tax receivable	0	514
Other prepaid taxes	1,306	1,240
Prepaid insurance	1,374	913
Prepaid rent	442	327
Prepaid Licenses	1,519	1,543
Inventory and other	2,358	1,134
Other current assets	$ 7,840	$ 7,868

Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

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An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date(s) within one year of the balance sheet date or the normal operating cycle, whichever is longer. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

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- Definition

The total of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer, and the aggregate carrying amount of current assets, as of the balance sheet date, not separately presented elsewhere in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer).

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- Definition

Carrying amount as of the balance sheet date of unamortized costs of insurance coverage, which will be charged against earnings ratably over the period in which contractually agreed upon coverage's will be in effect; such periods expire within one year or the normal operating cycle, if longer.

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- Definition

Carrying amount as of the balance sheet date of rental payments made in advance of the rental period; such amounts will be charged against earnings within one year or the normal operating cycle, if longer.

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