Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017
Cash Flows from Operating Activities
Net Income	$ 4,191	$ 5,938
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Depreciation and amortization	12,315	11,530
Property and equipment impairment due to restructuring	4,375	0
Stock-based compensation expense	2,115	3,164
Deferred income taxes	3,966	478
(Recovery of) provision for doubtful accounts	(30)	41
Other	9,050	(2,286)
Changes in Assets and Liabilities:
Accounts receivable	11,172	(5,767)
Contract assets	(81,663)	0
Inventories	29,417	(9,502)
Production cost of contracts	160	(1,777)
Other assets	1,475	938
Accounts payable	20,117	14,998
Contract liabilities	15,164	0
Accrued and other liabilities	(5,597)	(1,508)
Net Cash Provided by Operating Activities	26,227	16,247
Cash Flows from Investing Activities
Purchases of property and equipment	(7,513)	(16,242)
Proceeds from sale of assets	67	3
Payments for acquisition of Certified Thermoplastics Co., LLC, net of cash acquired	(30,993)	0
Net Cash Used in Investing Activities	(38,439)	(16,239)
Cash Flows from Financing Activities
Borrowings from senior secured revolving credit facility	189,600	123,000
Repayments of senior secured revolving credit facility	(175,000)	(110,800)
Repayments of term loan	0	(10,000)
Repayments of other debt	0	(3)
Net cash paid upon issuance of common stock under stock plans	(1,006)	(2,265)
Net Cash Provided by (Used in) Financing Activities	13,594	(68)
Net Increase (Decrease) in Cash and Cash Equivalents	1,382	(60)
Cash and Cash Equivalents at Beginning of Period	2,150	7,432
Cash and Cash Equivalents at End of Period	$ 3,532	$ 7,372