Net Loss per Share - Computation of Basic and Diluted Loss per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:
Net loss attributable to Vicor Corporation	$ (3,674)	$ (932)	$ (13,887)	$ (10,538)
Denominator:
Denominator for basic loss per share-weighted average shares	38,552	38,538	38,545	39,414
Effect of dilutive securities:
Employee stock options	0	0	0	0
Denominator for diluted loss per share - adjusted weighted-average shares and assumed conversions	38,552	38,538	38,545	39,414
Basic loss per share	$ (0.10)	$ (0.02)	$ (0.36)	$ (0.27)
Diluted loss per share	$ (0.10)	$ (0.02)	$ (0.36)	$ (0.27)