Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Vicor Corporation Stockholders' Equity [Member]	Noncontrolling Interest [Member]	Class B Common Stock [Member]
Beginning Balance at Dec. 31, 2017	$ 136,419	$ 401	$ 181,395	$ 93,605	$ (478)	$ (138,927)	$ 136,114	$ 305	$ 118
Sales of Common Stock	6,504	6	6,498				6,504
Stock-based compensation expense	2,604		2,604				2,604
Issuances of stock through employee stock purchase plan	1,874	1	1,873				1,874
Cumulative effect of adoption of new accounting principle (Topic 606)	3,670			3,670			3,670
Other	(3)	(6)	3				(3)
Components of comprehensive income, net of tax:
Net income	24,939			24,815			24,815	124
Other comprehensive income (loss)	(47)				(38)		(38)	(9)
Total comprehensive income	24,892						24,777	115
Ending Balance at Sep. 30, 2018	175,960	402	192,373	122,090	(516)	(138,927)	175,540	420	118
Beginning Balance at Jun. 30, 2018	158,938	399	188,276	109,078	(401)	(138,927)	158,543	395	118
Sales of Common Stock	2,465	3	2,462				2,465
Stock-based compensation expense	688		688				688
Issuances of stock through employee stock purchase plan	947		947				947
Components of comprehensive income, net of tax:
Net income	13,048			13,012			13,012	36
Other comprehensive income (loss)	(126)				(115)		(115)	(11)
Total comprehensive income	12,922						12,897	25
Ending Balance at Sep. 30, 2018	175,960	402	192,373	122,090	(516)	(138,927)	175,540	420	118
Beginning Balance at Dec. 31, 2018	184,090	402	193,457	129,000	(394)	(138,927)	183,656	434	118
Sales of Common Stock	1,118	1	1,117				1,118
Stock-based compensation expense	2,292		2,292				2,292
Issuances of stock through employee stock purchase plan	2,305	1	2,304				2,305
Other	(4)		(4)				(4)
Components of comprehensive income, net of tax:
Net income	12,794			12,786			12,786	8
Other comprehensive income (loss)	121				116		116	5
Total comprehensive income	12,915						12,902	13
Ending Balance at Sep. 30, 2019	202,716	404	199,166	141,786	(278)	(138,927)	202,269	447	118
Beginning Balance at Jun. 30, 2019	194,316	403	196,698	135,849	(278)	(138,927)	193,863	453	118
Sales of Common Stock	690	1	689				690
Stock-based compensation expense	753		753				753
Issuances of stock through employee stock purchase plan	1,026		1,026				1,026
Components of comprehensive income, net of tax:
Net income	5,932			5,937			5,937	(5)
Other comprehensive income (loss)	(1)							(1)
Total comprehensive income	5,931						5,937	(6)
Ending Balance at Sep. 30, 2019	$ 202,716	$ 404	$ 199,166	$ 141,786	$ (278)	$ (138,927)	$ 202,269	$ 447	$ 118