Financial Statement Components - Selected Financial Statement Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Inventories:
Raw materials and sub-assemblies	$ 26,784	$ 19,463
Work in process	12,862	7,723
Finished goods	8,103	7,919
Inventories	47,749	35,105
Inventories-delivered systems	2,856	1,912
Total inventories	50,605	37,017
Property, plant and equipment, net:
Total property, plant and equipment, gross	80,561	78,348
Accumulated depreciation and amortization	(36,068)	(28,715)
Total property, plant and equipment, net	44,493	49,633
Depreciation and amortization expense	6,900	6,600	$ 5,400
Accrued warranty	4,504	2,953
Accrued restructuring	256	997
Accrued professional services	481	778
Fair value of current portion of contingent payments to Zygo Corporation related to acquisition	945	1,385
Other	2,692	2,152
Total other current liabilities	8,878	8,265
Land [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	15,569	15,572
Building and improvements [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	20,158	19,641
Machinery and equipment [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	32,995	29,456
Furniture and fixtures [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	2,266	2,225
Software [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	8,245	7,942
Capital in progress [Member]
Property, plant and equipment, net:
Total property, plant and equipment, gross	$ 1,328	$ 3,512