Revenue and Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2017

Revenue and Accounts Receivable [Abstract]

Accounts Receivable Components

The components of accounts receivable are as follows (in thousands):

	December 31,
	2017			2016
Billed accounts receivable	$	11,736		$	13,164
Unbilled receivables		13,195			6,352
Allowance for doubtful accounts		(411	)		(429	)
	$	24,520		$	19,087

Allowance for Doubtful Accounts

The activities in the allowance for doubtful accounts are set forth below (in thousands):

	Balance Beginning of Year		Bad Debt Expenses (1)			Recoveries (2)		Balance End of Year
Year Ended December 31, 2017	$	429	$	(18	)	$	--	$	411
Year Ended December 31, 2016	$	485	$	(56	)	$	--	$	429
Year Ended December 31, 2015	$	372	$	113		$	--	$	485

(1)Accounts receivable reserves and reversal of allowance for subsequent collections, net

(2)Accounts receivable written-off and subsequent recoveries, net

Revenue by Customer Sector

We derived substantially all of our revenues from contracts and subcontracts with the U.S. Government. Revenue by customer sector for the last three fiscal years is as follows:

	2017				2016				2015
					(dollar amounts in thousands)
Federal	$	101,519	94.2	%	$	130,415	96.7	%	$	117,328	97.3	%
State & Local, and Commercial		6,208	5.8	%		4,453	3.3	%		3,306	2.7	%
Total	$	107,727	100.0	%	$	134,868	100.0	%	$	120,634	100.0	%