Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 39,991	$ 43,646
Trade and other receivables, less allowance for doubtful accounts of $503 and $477	24,241	28,990
Contract assets	44,845	44,502
Inventories	17,126	17,055
Prepaid expenses and other	5,683	6,562
Total current assets	131,886	140,755
Property and equipment, less accumulated depreciation and amortization of $75,660 and $74,311	78,349	78,756
Other assets	9,492	10,813
Total assets	219,727	230,324
Current liabilities:
Accounts payable	4,460	7,521
Accrued liabilities	5,105	6,563
Contract liabilities	1,155	2,599
Current portion of capital lease obligations	397	318
Total current liabilities	11,117	17,001
Capital lease obligations, less current portion	1,022	737
Deferred income taxes	354	941
Other long-term liabilities	10,967	11,381
Total liabilities	23,460	30,060
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $.01 par value, 10,000,000 shares authorized, none issued or outstanding
Common stock, $.01 par value, 15,000,000 shares authorized, 9,723,883 and 9,619,755 shares issued and outstanding	97	96
Additional paid-in-capital	118,635	119,856
Retained earnings	78,931	81,757
Accumulated other comprehensive loss	(1,396)	(1,445)
Total stockholders’ equity	196,267	200,264
Total liabilities and stockholders’ equity	$ 219,727	$ 230,324

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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- Definition

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).