Balance Sheet Information (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of property and equipment
Total property and equipment	$ 25,948	$ 24,426
Less: Accumulated depreciation and amortization	(13,602)	(12,606)
Land	1,770	1,770
Property and equipment, net	14,116	13,590
Building [Member]
Summary of property and equipment
Total property and equipment	6,207	6,207
Computers and office equipment [Member]
Summary of property and equipment
Total property and equipment	9,108	7,962
Manufacturing and Test Equipment [Member]
Summary of property and equipment
Total property and equipment	9,122	8,831
Furniture and fixtures [Member]
Summary of property and equipment
Total property and equipment	1,183	1,169
Leasehold improvements [Member]
Summary of property and equipment
Total property and equipment	301	230
Motor vehicles [Member]
Summary of property and equipment
Total property and equipment	$ 27	$ 27