Note 11 - Income Taxes (Details Textual) - USD ($)	12 Months Ended				24 Months Ended
	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	34.00%	34.00%
Effective Income Tax Rate Reconciliation, at Highest Federal Statutory Income Tax Rate, Percent			35.00%
Deferred Tax Liabilities, Net, Current		$ 0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 13,777,000	$ 39,907,000	$ 5,064,000
Earnings Per Share, Tax Holiday Effect		$ (0.05)	$ 0.18
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		$ 2,857,000
Decrease in Unrecognized Tax Benefits is Reasonably Possible		51,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total		17,000	$ 16,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total		65,000	113,000	222,000
Undistributed Earnings of Foreign Subsidiaries		38,470,000
Cumulative Effect on Retained Earnings, Net of Tax, Total			(1,217,000)	5,261,000
Accounting Standards Update 2016-16 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total		1,217,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total		219,900,000
Tax Credit Carryforward, Amount		47,227,000
Domestic Tax Authority [Member] | Cortina Systems Inc. [Member]
Operating Loss Carryforwards, Total		49,152,000
Domestic Tax Authority [Member] | ClariPhy Communications Inc.[Member]
Operating Loss Carryforwards, Total		46,601,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member] | Cortina Systems Inc. [Member]
Tax Credit Carryforward, Amount		6,033,000
Domestic Tax Authority [Member] | Tax Year 2018 [Member]
Operating Loss Carryforwards, Total		18,559,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total		96,572,000
Tax Credit Carryforward, Amount		49,179,000
State and Local Jurisdiction [Member] | Cortina Systems Inc. [Member]
Operating Loss Carryforwards, Total		3,919,000
State and Local Jurisdiction [Member] | ClariPhy Communications Inc.[Member]
Operating Loss Carryforwards, Total		68,177,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member] | Cortina Systems Inc. [Member]
Tax Credit Carryforward, Amount		7,912,000
State and Local Jurisdiction [Member] | Canada Revenue Agency [Member]
Tax Credit Carryforward, Amount		6,494,000
State and Local Jurisdiction [Member] | Canada Revenue Agency [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount		3,396,000
Foreign Tax Authority [Member]
Increase (Decrease) in Income Taxes		(2,093,000)	7,412,000
Foreign Tax Authority [Member] | Tax Authority, Taiwan [Member]
Operating Loss Carryforwards, Total		2,848,000
Foreign Tax Authority [Member] | Her Majesty's Revenue and Customs (HMRC) [Member]
Operating Loss Carryforwards, Total		$ 7,631,000
Foreign Tax Authority [Member] | Inland Revenue, Singapore (IRAS) [Member]
Effective Income Tax Rate Reconciliation, Tax Holiday, Percent		5.00%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent		17.00%
Foreign Tax Authority [Member] | Administracion Federal de Ingresos Publicos (AFIP) [Member] | Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent	25.00%				12.00%
Foreign Tax Authority [Member] | Tax Year 2010 [Member] | Inland Revenue, Singapore (IRAS) [Member]
Open Tax Year		2010
Foreign Tax Authority [Member] | Tax Year 2011 [Member] | Inland Revenue, Singapore (IRAS) [Member]
Open Tax Year		2011
Foreign Tax Authority [Member] | Tax Year 2012 [Member] | Inland Revenue, Singapore (IRAS) [Member]
Open Tax Year		2012
Increase to Other Comprehensive Income [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 20,000	134,000	305,000
Increase to Income Tax Provision [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 13,757,000	39,931,000	10,647,000
Decrease to Goodwill [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount			$ (158,000)
Decrease to Additional Paid-in Capital [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount				(16,044,000)
Increase to Goodwill [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount				3,088,000
Increase to Retained Earnings [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount				$ 7,068,000