Segment Information - Total Assets by Segment (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Total assets
Total assets	$ 117,193,000	$ 107,137,000
Operating Segments [Member] | SLPE [Member]
Total assets
Total assets	39,195,000	36,419,000
Operating Segments [Member] | High Power Group [Member]
Total assets
Total assets	34,383,000	31,296,000
Operating Segments [Member] | SL-MTI [Member]
Total assets
Total assets	14,374,000	12,012,000
Operating Segments [Member] | RFL [Member]
Total assets
Total assets	13,756,000	13,744,000
Unallocated Corporate Expenses [Member]
Total assets
Total assets	$ 15,485,000	$ 13,666,000