Note 5 - Accounts Receivable, Net - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Accounts receivable, gross	$ 75,051	$ 77,503
Less: allowance for doubtful accounts	(1,896)	(1,992)
Accounts receivable, net	73,155	75,511
Billed [Member]
Accounts receivable, gross	47,267	53,756
Unbilled [Member]
Accounts receivable, gross	27,261	23,237
Contract Retentions [Member]
Accounts receivable, gross	$ 523	$ 510

For unclassified balance sheet, amounts due from customers or clients for goods or services that have been delivered or sold in the normal course of business.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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+ References

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