Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 26, 2016		Mar. 28, 2015
Cash flows from operating activities:
Net loss	$ (1,911,000)		$ (2,740,000)
Reconciliation of net loss to net cash provided by (used in) operating activities:
Loss on disposal of assets	$ 32,000
Operating cash flows of discontinued operations			$ (463,000)
Depreciation and amortization	$ 2,669,000		2,910,000
Share-based compensation expense	1,957,000		1,698,000
Deferred income taxes	$ (535,000)		(781,000)
Asset impairment charge			273,000
Changes in other accrued liabilities	$ 28,000		297,000
Changes in other assets	(26,000)		(78,000)
Changes in current assets and liabilities, excluding effects from divestitures:
Accounts receivable	(5,258,000)		7,685,000
Inventories	(2,518,000)		(5,474,000)
Other current assets	(1,856,000)		577,000
Accounts payable	5,053,000		5,578,000
Deferred profit	1,817,000		502,000
Income taxes payable, including excess stock option exercise benefit	487,000		505,000
Accrued compensation, warranty and other liabilities	(1,398,000)		(6,274,000)
Net cash provided by (used in) operating activities	(1,459,000)		$ 4,215,000
Cash flows from investing activities, excluding effects from divestitures:
Purchases of short-term investments	(8,891,000)
Sales and maturities of short-term investments	967,000		$ 45,000
Purchases of property, plant and equipment	(895,000)		$ (1,056,000)
Cash received from sale of assets	$ 813,000
Investing cash flows of discontinued operations			$ (15,000)
Net cash used in investing activities	$ (8,006,000)		(1,026,000)
Cash flows from financing activities:
Cash dividends paid	(1,573,000)		(1,539,000)
Repurchases of common stock	(395,000)		(1,230,000)
Net cash used in financing activities	(1,968,000)		(2,769,000)
Effect of exchange rate changes on cash and cash equivalents	1,008,000		(2,696,000)
Net decrease in cash and cash equivalents	(10,425,000)		(2,276,000)
Cash and cash equivalents at beginning of period	115,370,000	[1]	70,885,000
Cash and cash equivalents at end of period	104,945,000		68,609,000
Supplemental disclosure of cash flow information:
Cash paid (refunded) for income taxes	248,000		(703,000)
Inventory capitalized as property, plant and equipment	115,000		97,000
Dividends declared but not yet paid	$ 1,575,000		$ 1,543,000

[1] Derived from December 26, 2015 audited financial statements