Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales	$ 103,102	$ 79,783	$ 79,355	$ 67,219	$ 90,560	$ 82,883	$ 86,320	$ 74,650	$ 329,459	$ 334,413	$ 341,573
Long-lived Assets	116,583				101,116				116,583	101,116	80,969
North America
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									109,457	83,546	90,000
Long-lived Assets	49,132				33,564				49,132	33,564	16,811
United States
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									105,764	79,013	84,673
Long-lived Assets	49,132				33,564				49,132	33,564	16,811
Other
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									3,693	4,533	5,327
Europe
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									100,126	121,008	104,825
Long-lived Assets	39,786				39,137				39,786	39,137	37,946
Switzerland
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									6,063	9,622	10,117
Long-lived Assets	37,055				38,121				37,055	38,121	36,540
England
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									21,090	28,328	24,421
Long-lived Assets	645				739				645	739	1,082
Germany
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									40,277	39,595	26,483
Long-lived Assets	1,943				267				1,943	267	299
Other
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									32,696	43,463	43,804
Long-lived Assets	143				10				143	10	25
Asia
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									119,876	129,859	146,748
Long-lived Assets	27,665				28,415				27,665	28,415	26,212
China
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									96,532	102,550	111,684
Long-lived Assets	12,468				12,405				12,468	12,405	10,705
Taiwan
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									4,541	5,474	11,454
Long-lived Assets	15,197				16,010				15,197	16,010	15,507
Other
Summary, by country, of sales from external customers and of net property, plant and equipment
Sales									$ 18,803	$ 21,835	$ 23,610