Note 5 - Balance Sheet Components (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Refund Receivable	$ 4,297		[1]
Depreciation, Total	$ 11,400	$ 14,000		$ 12,600

[1] In December 2018, a supplier terminated a prepaid wafer purchase agreement with the Company and agreed to refund the Company the remaining wafer purchase prepayment of $4.3 million, which was recorded as a receivable as of December 31, 2018.