Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 23,198	$ 37,927
Trade and other receivables, less allowance for doubtful accounts of $335 and $767	33,778	42,680
Contract assets	90,504	76,985
Inventories	30,029	29,177
Prepaid expenses and other	4,035	5,194
Total current assets	181,544	191,963
Property and equipment, less accumulated depreciation and amortization of $101,621 and $96,684	110,007	110,184
Operating lease right-of-use assets	33,522	30,813
Goodwill	22,985	22,985
Intangible assets, net	9,887	10,518
Other assets	6,164	6,552
Total assets	364,109	373,015
Current liabilities:
Current portion of long-term debt	0	7,701
Accounts payable	15,460	12,993
Accrued liabilities	14,988	16,814
Contract liabilities	2,722	6,189
Current portion of operating lease liabilities	2,406	2,204
Total current liabilities	35,576	45,901
Long-term debt	0	5,888
Operating lease liabilities	30,631	27,911
Deferred income taxes	12,548	12,481
Other long-term liabilities	10,642	11,208
Total liabilities	89,397	103,389
Commitments and contingencies (Note 8)
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, 9,870,567 and 9,805,437 shares issued and outstanding	99	98
Additional paid-in-capital	123,686	123,013
Retained earnings	152,687	148,381
Accumulated other comprehensive loss	(1,760)	(1,866)
Total stockholders’ equity	274,712	269,626
Total liabilities and stockholders’ equity	$ 364,109	$ 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).