Note 5 - Balance Sheet Components - Other Long-term Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred compensation plan assets	$ 28,080	$ 20,288
Prepaid wafer purchase		5,000
Other prepaid expense	897	1,117
Other	1,091	1,006
Total	$ 30,068	$ 27,411