Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 29,893	$ 37,927
Trade and other receivables, less allowance for doubtful accounts of $782 and $767	40,214	42,680
Contract assets	75,466	76,985
Inventories	33,177	29,177
Prepaid expenses and other	5,560	5,194
Total current assets	184,310	191,963
Property and equipment, less accumulated depreciation and amortization of $98,702 and $96,684	109,423	110,184
Operating lease right-of-use assets	34,228	30,813
Goodwill	22,985	22,985
Intangible assets, net	10,202	10,518
Other assets	6,167	6,552
Total assets	367,315	373,015
Current liabilities:
Current portion of long-term debt	3,131	7,701
Accounts payable	13,260	12,993
Accrued liabilities	14,607	16,814
Contract liabilities	2,034	6,189
Current portion of operating lease liabilities	2,382	2,204
Total current liabilities	35,414	45,901
Long-term debt	5,106	5,888
Operating lease liabilities	31,236	27,911
Deferred income taxes	12,750	12,481
Other long-term liabilities	10,472	11,208
Total liabilities	94,978	103,389
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $.01 par value, 10,000,000 shares authorized, none issued or outstanding	0	0
Common stock, $.01 par value, 15,000,000 shares authorized, 9,857,961 and 9,805,437 shares issued and outstanding	99	98
Additional paid-in-capital	123,487	123,013
Retained earnings	150,556	148,381
Accumulated other comprehensive loss	(1,805)	(1,866)
Total stockholders’ equity	272,337	269,626
Total liabilities and stockholders’ equity	$ 367,315	$ 373,015

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).