Significant Accounting Policies - Computation Of Basic And Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income (loss) attributable to Vicor Corporation	$ 6,910	$ 13,012	$ 7,860	$ 3,943	$ 1,611	$ (11)	$ (459)	$ (974)	$ 31,725	$ 167	$ (6,247)
Denominator:
Denominator for basic net income (loss) per share-weighted average shares									39,872	39,228	38,842
Effect of dilutive securities:
Employee stock options									857	705
Denominator for diluted net income (loss) per share - adjusted weighted-average shares and assumed conversions									40,729	39,933	38,842
Basic net income (loss) per share	$ 0.17	$ 0.32	$ 0.20	$ 0.10					$ 0.80	$ 0.00	$ (0.16)
Diluted net income (loss) per share	$ 0.17	$ 0.32	$ 0.19	$ 0.10					$ 0.78	$ 0.00	$ (0.16)