Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Stock-Based Compensation and Employee Benefit Plans - Stock Options (Details)

v3.8.0.1
Stock-Based Compensation Stock-Based Compensation and Employee Benefit Plans - Stock Options (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value $ 6,600 $ 6,500 $ 16,300
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 1 year 10 months 24 days    
Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Expected life (in years)   6 months 6 months
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate 0.00% 0.00% 0.00%
Employee Stock [Member] | Exar Corporation [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value $ 31.12    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate 0.00%    
Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number 3,069 3,025  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (835)    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares (255)    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]      
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price $ 8.95 $ 6.78  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price 9.42    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price $ 19.50    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable [Table Text Block] 3025    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options 2,613    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price $ 8.84    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price $ 7.86    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term 2 years 6 months 29 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term 2 years 6 months 15 days    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term 2 years 2 months 1 day    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value $ 53,686    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value 53,243    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value $ 48,548    
Stock Option [Member] | Exar Corporation [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Number of Shares, Period Increase (Decrease) 1,135    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease), Weighted Average Exercise Price $ 17.44    
Minimum [Member] | Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 60.00% 0.38% 0.09%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Expected life (in years) 4 months 17 days    
Volatility 29.56% 49.94% 32.65%
Minimum [Member] | Employee Stock [Member] | Exar Corporation [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.29%    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Expected life (in years) 1 year 7 months 6 days    
Volatility 45.39%    
Maximum [Member] | Employee Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.39% 0.60% 0.33%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Expected life (in years) 6 months    
Volatility 49.94% 53.94% 59.14%
Maximum [Member] | Employee Stock [Member] | Exar Corporation [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.99%    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]      
Expected life (in years) 6 years    
Volatility 50.32%