Net Income (Loss) per Share - Computation Of Basic And Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income (loss) attributable to Vicor Corporation	$ 7,860	$ (459)	$ 11,803	$ (1,433)
Denominator:
Denominator for basic net income (loss) per share-weighted average shares	39,709	39,172	39,594	39,121
Effect of dilutive securities:
Employee stock options	937		812
Denominator for diluted net income (loss) per share - adjusted weighted-average shares and assumed conversions	40,646	39,172	40,406	39,121
Basic net income (loss) per share	$ 0.20	$ (0.01)	$ 0.30	$ (0.04)
Diluted net income (loss) per share	$ 0.19	$ (0.01)	$ 0.29	$ (0.04)