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Stock-Based Compensation and Employee Benefit Plans - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Nov. 11, 2011
Sep. 30, 2016
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Term of Option     10 years      
Employee's compensation plan     The Company matches employee contributions to the plan at a rate of 50%, up to the first 3% of an employee’s compensation.      
Employee contributions     20.00%      
Company contribution to the plan     $ 976,000 $ 937,000 $ 882,000  
Minimum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Employees pre-tax salary     1.00%      
Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Employees pre-tax salary     80.00%      
Vi Chip Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Non-qualified stock options     10,414,000 13,092,250    
Stock options, grants in period     0      
Maturity period of US Treasury Bond     7 years      
Chip options actually vest forfeiture     89.00% 76.00% 76.00%  
Annual forfeiture rate     4.25% 9.00% 9.00%  
Share exercisable     2,743,400 810,700 7,074,650  
Weighted average exercise prices     $ 0.97 $ 1.00 $ 1.00  
Options Exercised     $ 0 $ 0 $ 0  
Fair value of stock options that vested     0 $ 2,900,000 $ 0  
Total unrecognized compensation cost     $ 1,792,000      
Compensation cost recognized over a weighted-average period     3 years 4 months 24 days      
Expected recognized expenses, Year One     $ 544,000      
Expected recognized expenses, Year Two     503,000      
Expected recognized expenses, Year Three     483,000      
Expected recognized expenses, Year Four     $ 262,000      
Weighted-average fair value       $ 0.29 $ 0.01  
2000 Plan, Vicor [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Common Stock reserved for issuance     10,000,000      
Non-qualified stock options granted to non-employees     85.00%      
Non-qualified stock options     1,382,981 1,365,917    
Stock options, grants in period     684,077      
Chip options actually vest forfeiture     85.00% 85.00% 86.00%  
Annual forfeiture rate     5.25% 5.25% 5.00%  
Share exercisable     888,257 707,244 730,388  
Weighted average exercise prices     $ 8.93 $ 8.01 $ 7.74  
Total Intrinsic value     $ 22,938,000 $ 4,395,000 $ 1,392,000  
Options Exercised     6,782,000 3,295,000 1,572,000  
Fair value of stock options that vested     2,921,000 $ 774,000 $ 365,000  
Total unrecognized compensation cost     $ 2,487,000      
Compensation cost recognized over a weighted-average period     1 year 10 months 24 days      
Expected recognized expenses, Year One     $ 1,183,000      
Expected recognized expenses, Year Two     689,000      
Expected recognized expenses, Year Three     395,000      
Expected recognized expenses, Year Four     180,000      
Expected recognized expenses, Year Five     $ 40,000      
Weighted-average fair value     $ 17.46 $ 8.71 $ 4.94  
Stock Bonus Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Common stock purchase by non-employees     109,964      
2007 VI Chip Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Common Stock reserved for issuance     14,000,000      
Non-qualified stock options     0     2,984,250
Stock options, grants in period 0          
Stock-based compensation expense reversed   $ 768,000        
2007 VI Chip Plan [Member] | Cost of Revenues [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Decrease in costs and expenses due to reversal of share-based compensation expense   86,000        
2007 VI Chip Plan [Member] | Selling, General and Administrative [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Decrease in costs and expenses due to reversal of share-based compensation expense   516,000        
2007 VI Chip Plan [Member] | Research and Development [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Decrease in costs and expenses due to reversal of share-based compensation expense   $ 166,000        
2017 Employee Stock Purchase Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Non-qualified stock options granted to non-employees     85.00%      
Maximum number of shares authorized for issuances     2,000,000      
Maximum percentage of payroll deductions on employee's compensation     15.00%      
Offering period of employee stock purchase plan     6 months