Vicor (VICR) 10-Q 30 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Entity Registrant Name	VICOR CORP
Entity Central Index Key	751978
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding	26,771,119
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding	11,767,052

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$61,188	$84,554
Accounts receivable, less allowance of $280 in 2013 and $292 in 2012	28,321	27,165
Inventories, net	27,987	29,955
Deferred tax assets	2,248	1,776
Other current assets	3,497	2,613
Total current assets	123,241	146,063
Long-term investments, net	6,231	6,736
Property, plant and equipment, net	40,457	44,092
Long-term deferred tax assets, net	9,045	3,523
Other assets	1,904	2,167
Total assets	180,878	202,581
Current liabilities:
Accounts payable	9,772	6,812
Accrued compensation and benefits	8,907	7,400
Accrued expenses	2,298	2,233
Accrued severance charges	249
Income taxes payable		336
Deferred revenue	911	784
Total current liabilities	22,137	17,565
Long-term deferred revenue	1,118	1,549
Long-term income taxes payable	1,527	1,494
Total liabilities	24,782	20,608
Commitments and contingencies (Note 12)
Vicor Corporation stockholders' equity:
Common Stock	391	390
Additional paid-in capital	169,409	167,498
Retained earnings	121,747	132,285
Accumulated other comprehensive loss	-274	-112
Treasury stock, at cost	-138,927	-121,827
Total Vicor Corporation stockholders' equity	152,464	178,352
Noncontrolling interest	3,632	3,621
Total equity	156,096	181,973
Total Liabilities and equity	180,878	202,581
Class B Common Stock [Member]
Vicor Corporation stockholders' equity:
Common Stock	$118	$118

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Statement Of Financial Position [Abstract]
Accounts receivable, less allowance	$280	$292

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Net revenues	$55,091	$52,948	$143,902	$168,083
Cost of revenues	32,111	29,995	85,854	96,557
Gross margin	22,980	22,953	58,048	71,526
Operating expenses:
Selling, general and administrative	14,478	13,425	43,820	41,250
Research and development	9,857	9,232	29,700	28,807
Severance charges			1,361
Total operating expenses	24,335	22,657	74,881	70,057
Income (loss) from operations	-1,355	296	-16,833	1,469
Other income (expense), net:
Total unrealized gains on available-for-sale securities, net of unrealized losses	65	351	103	581
Portion of losses recognized in other comprehensive income (loss)	-64	-339	-181	-565
Net credit gains (losses) recognized in earnings	1	12	-78	16
Other income, net:	50	58	90	189
Total other income (expense), net	51	70	12	205
Income (loss) before income taxes	-1,304	366	-16,821	1,674
(Benefit) provision for income taxes	-406	86	-6,337	809
Consolidated net income (loss)	-898	280	-10,484	865
Less: Net income attributable to noncontrolling interest	34	89	54	128
Net income (loss) attributable to Vicor Corporation	($932)	$191	($10,538)	$737
Net income (loss) per common share attributable to Vicor Corporation:
Basic	($0.02)		($0.27)	$0.02
Diluted	($0.02)		($0.27)	$0.02
Shares used to compute net income (loss) per share attributable to Vicor Corporation:
Basic	38,538	41,811	39,414	41,811
Diluted	38,538	41,815	39,414	41,818

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income (loss)	($898)		$280		($10,484)		$865
Foreign currency translation gains (losses), net of tax provision (benefit)	22	[1]	82	[1]	-381	[1]	-31	[1]
Unrealized gains on available-for-sale securities	61	[2]	339	[2]	176	[2]	565	[2]
Consolidated comprehensive income (loss)	-815		701		-10,689		1,399
Less: Comprehensive income attributable to noncontrolling interest	36		99		11		126
Comprehensive income (loss) attributable to Vicor Corporation	($851)		$602		($10,700)		$1,273
[1]	Net of tax provision of $12 and $48 for the three months ended September 30, 2013 and 2012, respectively. Net of tax benefit of $(205) and $(26) for the nine months ended September 30, 2013 and 2012, respectively.
[2]	The deferred tax assets associated with the unrealized gains on available-for-sale securities are completely offset by a tax valuation allowance as of September 30, 2013 and 2012. Therefore, there is no net income tax provision (benefit) recognized for the three and nine months ended September 30, 2013 and 2012.

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Foreign currency translation losses, tax benefit	$12	$48	($205)	($26)
Recognized income tax provision (benefit)	$0	$0	$0	$0

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Consolidated net income (loss)	($10,484)	$865
Adjustments to reconcile consolidated net income (loss) to net cash provided by (used for) operating activities:
Depreciation and amortization	7,555	7,870
Deferred income taxes	-5,491	-88
Stock-based compensation expense	1,893	970
Decrease in long-term deferred revenue	-104	-107
Excess tax benefit of stock-based compensation	-53	-78
Gain on disposal of equipment	-3	-31
Credit loss (gain) on available-for-sale securities	78	-16
Increase (decrease) in long-term income taxes payable	33	-10
Change in current assets and liabilities, net	3,896	4,932
Net cash (used for) provided by operating activities	-2,680	14,307
Investing activities:
Additions to property, plant and equipment	-4,027	-4,838
Sales and maturities of investments	603	3,540
Purchases of investments		-270
Proceeds from sale of equipment	3	31
Decrease in other assets	49	4
Net cash used in investing activities	-3,372	-1,533
Financing activities:
Purchases of Common Stock	-17,100
Proceeds from issuance of Common Stock	58	9
Excess tax benefit of stock-based compensation	53	78
Net cash (used for) provided by financing activities	-16,989	87
Effect of foreign exchange rates on cash	-325	-17
Net (decrease) increase in cash and cash equivalents	-23,366	12,844
Cash and cash equivalents at beginning of period	84,554	71,908
Cash and cash equivalents at end of period	$61,188	$84,752

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Basis of Presentation	1. Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements of Vicor Corporation (the “Company”) have been prepared in accordance with generally accepted accounting principles for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, these interim financial statements do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.
	In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2013, are not necessarily indicative of the results that may be expected for any other interim period or the year ending December 31, 2013. The balance sheet at December 31, 2012, presented herein has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. For further information, refer to the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012, (File No. 0-18277) filed by the Company with the Securities and Exchange Commission.

LongTerm_Investments

Long-Term Investments	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]
Long-Term Investments	2. Long-Term Investments
	The Company’s principal sources of liquidity are its existing balances of cash and cash equivalents, as well as cash generated from operations. Consistent with the Company’s investment policy guidelines, the Company can invest, and has historically invested, its cash balances in demand deposit accounts, money market funds, brokered certificates of deposit, and auction rate securities meeting certain quality criteria. All of the Company’s investments are subject to credit, liquidity, market, and interest rate risk.
	The Company’s long-term investments are classified as available-for-sale securities. Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of tax, attributable to credit loss recorded through the statement of operations and unrealized gains and losses, net of tax, attributable to other non-credit factors recorded in “Accumulated other comprehensive loss”, a component of Stockholders’ Equity. In determining the amount of credit loss, the Company compares the present value of cash flows expected to be collected to the amortized cost basis of the securities, considering credit default risk probabilities and changes in credit ratings as significant inputs, among other factors.
	The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, the net amount of which, along with interest and realized gains and losses, is included in “Other income (expense), net” in the Condensed Consolidated Statements of Operations. The Company periodically evaluates investments to determine if impairment is required, whether an impairment is other than temporary, and the measurement of an impairment loss. The Company considers a variety of impairment indicators such as, but not limited to, a significant deterioration in the earnings performance, credit rating, or asset quality of the investment.
	As of September 30, 2013, the Company held par value of $6,000,000 of auction rate securities. These auction rate securities consist of collateralized debt obligations, supported by pools of student loans, sponsored by state student loan agencies and corporate student loan servicing firms. The interest rates for these securities are reset at auction at regular intervals of 28 days. The auction rate securities held by the Company traded at par prior to February 2008 and are callable at par at the option of the issuer.
	Until February 2008, the auction rate securities market was liquid, as the investment banks conducting the periodic “Dutch auctions” by which interest rates for the securities had been established had committed their capital to support such auctions in the event of insufficient third-party investor demand. Starting the week of February 11, 2008, a substantial number of auctions failed, as demand from third-party investors weakened and the investment banks conducting the auctions chose not to commit capital to support such auctions (i.e., investment banks chose not to purchase securities themselves in order to balance supply and demand, thereby facilitating a successful auction, as they had done in the past). The consequences of a failed auction are (a) an investor must hold the specific security until the next scheduled auction (unless that investor chooses to sell the security to a third party outside of the auction process) and (b) the interest rate on the security generally resets to an interest rate set forth in each security’s indenture.
	As of September 30, 2013, the Company held auction rate securities that had experienced failed auctions totaling $6,000,000 at par value, all of which had been purchased through and are held by a broker-dealer affiliate of Bank of America, N.A. (the “Failed Auction Securities”). The Failed Auction Securities held by the Company are Aaa/AA+/A3/BBB rated by major credit rating agencies, collateralized by student loans, and guaranteed by the U.S. Department of Education under the Federal Family Education Loan Program. Management is not aware of any reason to believe any of the issuers of the Failed Auction Securities held by the Company are presently at risk of default. Through September 30, 2013, the Company has continued to receive interest payments on the Failed Auction Securities in accordance with the terms of their respective indentures. Management believes the Company ultimately should be able to liquidate all of its Failed Auction Securities without significant loss primarily due to the overall quality of the issues held and the collateral securing the substantial majority of the underlying obligations. However, current conditions in the auction rate securities market have led management to conclude the recovery period for the Failed Auction Securities exceeds 12 months. As a result, the Company continued to classify the Failed Auction Securities as long-term as of September 30, 2013.
	The following is a summary of available-for-sale securities (in thousands):
					Gross			Gross		Estimated
					Unrealized			Unrealized		Fair
	September 30, 2013	Cost			Gains			Losses		Value
	Failed Auction Securities	$	6,000		$	—		$	1,018	$	4,982
	Brokered certificates of deposit		1,010			8			—		1,018
	Certificate of deposit		231			—			—		231
		$	7,241		$	8		$	1,018	$	6,231
					Gross			Gross		Estimated
					Unrealized			Unrealized		Fair
	December 31, 2012	Cost			Gains			Losses		Value
	Failed Auction Securities	$	6,100		$	—		$	1,121	$	4,979
	Brokered certificates of deposit		1,280			12			—		1,292
	Certificates of deposit		465			—			—		465
		$	7,845		$	12		$	1,121	$	6,736
	All of the Failed Auction Securities as of September 30, 2013, have been in an unrealized loss position for greater than 12 months.
	The amortized cost and estimated fair value of available-for-sale securities on September 30, 2013, by contractual maturities, are shown below (in thousands):
					Estimated
		Cost			Fair Value
	Due in one year or less	$	611		$	612
	Due in two to ten years		630			637
	Due in ten to twenty years		—			—
	Due in twenty to forty years		6,000			4,982
		$	7,241		$	6,231
	Based on the fair value measurements described in Note 3, the fair value of the Failed Auction Securities on September 30, 2013, with a par value of $6,000,000, was estimated by the Company to be approximately $4,982,000, an increase in fair value of $103,000 from December 31, 2012. The gross unrealized loss of $1,018,000 on the Failed Auction Securities consists of two types of estimated loss: an aggregate credit loss of $395,000 and an aggregate temporary impairment of $623,000. For the nine months ended September 30, 2013, the aggregate credit loss on the Failed Auction Securities increased by a net amount of $78,000, which was recorded in “Net credit gains (losses) recognized in earnings” in the Condensed Consolidated Statement of Operations. In determining the amount of credit loss, the Company compared the present value of cash flows expected to be collected to the amortized cost basis of the securities, considering credit default risk probabilities and changes in credit ratings as significant inputs, among other factors (See Note 3).
	The following table represents a roll forward of the activity related to the credit loss recognized in earnings on available-for-sale auction rate securities held by the Company for the nine months ended September 30 (in thousands):
		2013			2012
	Balance at the beginning of the period	$	317		$	308
	Additions for the amount related to credit loss for which other-than- temporary impairment was not previously recognized		85			—
	Reduction for security sold during the period		(7	)		(16	)
	Balance at the end of the period	$	395		$	292
	At this time, the Company has no intent to sell any of the impaired Failed Auction Securities and does not believe it is more likely than not the Company will be required to sell any of these securities. If current market conditions deteriorate further, the Company may be required to record additional unrealized losses. If the credit rating of the security deteriorates, the Company may be required to adjust the carrying value of these investments through impairment charges recorded in the Condensed Consolidated Statement of Operations, and any such impairment adjustments may be material.
	Based on the Company’s ability to access cash and cash equivalents and its expected operating cash flows, management does not anticipate the current lack of liquidity associated with the Failed Auction Securities held will affect the Company’s ability to execute its current operating plan.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements
	The Company accounts for certain financial assets at fair value, defined as the price that would be received to sell an asset or paid to transfer a liability (i.e., an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions market participants would use in pricing an asset or liability. A three-level hierarchy is used to show the extent and level of judgment used to estimate fair value measurements.
	Assets measured at fair value on a recurring basis include the following as of September 30, 2013 (in thousands):
		Using
		Quoted Prices			Significant			Significant		Total Fair
		in Active			Other			Unobservable		Value as of
		Markets			Observable			Inputs		September 30, 2013
		(Level 1)			Inputs			(Level 3)
					(Level 2)
	Cash Equivalents:
	Money market funds	$	12,485		$	—		$	—	$	12,485
	Long-term investments:
	Failed Auction Securities		—			—			4,982		4,982
	Brokered certificates of deposit		—			1,018			—		1,018
	Certificate of deposit		231			—			—		231
	The Company has brokered certificates of deposit classified as Level 2 because the fair value for these investments has been determined utilizing observable inputs from non-active markets. The fair values fluctuate with changes in market interest rates obtained from information available in publicly quoted markets. Management tested the reported fair values by comparing them to net present value calculations utilizing a discount rate based on U.S. Treasury bill and bond yields for similar maturities.
	As of September 30, 2013, there was insufficient observable auction rate security market information available to determine the fair value of the Failed Auction Securities using Level 1 or Level 2 inputs. As such, the Company’s investments in Failed Auction Securities were deemed to require valuation using Level 3 inputs. Management, after consulting with advisors, valued the Failed Auction Securities using analyses and pricing models similar to those used by market participants (i.e., buyers, sellers, and the broker-dealers responsible for execution of the Dutch auction pricing mechanism by which each issue’s interest rate was set). Management utilized a probability weighted discounted cash flow (“DCF”) model to determine the estimated fair value of these securities as of September 30, 2013. The major assumptions used in preparing the DCF model included: estimates for the amount and timing of future interest and principal payments based on default probability assumptions used to measure the credit loss of 6.4%; the rate of return required by investors to own these securities in the current environment, which management estimates to be 5.0% above the risk free rate of return; and an estimated timeframe of three to five years for successful auctions for these securities to occur. In making these assumptions, management considered relevant factors including: the formula applicable to each security defining the interest rate paid to investors in the event of a failed auction (the “Penalty Rate”); forward projections of the interest rate benchmarks specified in such formulas; the likely timing of principal repayments; the probability of full repayment considering the guarantees by the U.S. Department of Education of the underlying student loans, guarantees by other third parties, and additional credit enhancements provided through other means; and publicly available pricing data for recently issued student loan asset-backed securities not subject to auctions. In developing its estimate of the rate of return required by investors to own these securities, management compared the Penalty Rates of the Failed Auction Securities with yields of actively traded long-term bonds with similar characteristics and, reflecting the limited liquidity for auction rate securities and the discounts to par value seen in recent tender offers by issuers and arms’ length market transactions between informed buyers and sellers, estimated the implied yield (i.e., the discount to par value) necessary to complete a sale of the Failed Auction Securities. Management has calculated an increase or decrease in the liquidity risk premium of 5.0% referenced above of 1.0% (i.e., 100 basis points) as used in the model, would decrease or increase, respectively, the fair value of the Failed Auction Securities by approximately $300,000.
	For purposes of the valuation process for the Failed Auction Securities, “management” consists of senior members of the Company’s finance department. The fair value measurements for the Failed Auction Securities are reviewed and updated on a quarterly basis. The calculations are prepared by the Company’s Corporate Controller, in conjunction with information provided by its valuation advisors, and include the development and substantiation of the unobservable inputs. The methodology, assumptions, and calculations are reviewed and approved by the Company’s Chief Financial Officer and Chief Accounting Officer.
	The significant unobservable inputs used in the fair value measurement of the Company’s Failed Auction Securities are the cumulative probability of earning the maximum rate until maturity, the cumulative probability of principal return prior to maturity, the cumulative probability of default, the liquidity risk premium, and the recovery rate in default. Significant increases (decreases) in any of those inputs in isolation would result in changes in fair value measurement. Significant increases (decreases) in the cumulative probability of earning the maximum rate until maturity, the cumulative probability of principal return prior to maturity, and the recovery rate in default would result in a higher (lower) fair value measurement, while increases (decreases) in the cumulative probability of default and the liquidity risk premium would result in a lower (higher) fair value measurement.
	Generally, the interrelationships are such that a change in the assumption used for the cumulative probability of principal return prior to maturity is accompanied by a directionally similar change in the assumption used for the cumulative probability of earning the maximum rate until maturity and a directionally opposite change in the assumptions used for the cumulative probability of default and the liquidity risk premium. The recovery rate in default is somewhat independent and based upon the securities’ specific underlying assets and published recovery rate indices.
	Quantitative information about Level 3 fair value measurements as of September 30, 2013 are as follows (dollars in thousands):
								Range
					Valuation		Unobservable	(Weighted
		Fair Value			Technique		Input	Average)
	Failed Auction Securities	$	4,982		Discounted		Cumulative probability of earning the maximum rate until maturity	0.01% - 0.05%
					cash flow			-0.03%
							Cumulative probability of principal return prior to maturity	74.24% - 95.60%
								-84.92%
							Cumulative probability of default	4.39% - 25.71%
								-15.05%
							Liquidity risk premium	5.00% - 5.00%
								-5.00%
							Recovery rate in default	40.00% - 40.00%
								-40.00%
	The following table summarizes the change in the estimated fair values calculated for those assets valued on a recurring basis utilizing Level 3 inputs (i.e., the Failed Auction Securities) for the nine months ended September 30, 2013 (in thousands):
	Balance at the beginning of the period	$	4,979
	Redemptions, at par		(100	)
	Credit loss on available-for-sale securities included in Other income (expense), net		(78	)
	Unrealized gain included in Other comprehensive income (loss)		181
	Balance at the end of the period	$	4,982

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	4. Stock-Based Compensation
	The Company uses the Black-Scholes option pricing model to calculate the fair value of stock option awards as of their grant date. Stock-based compensation expense for the three and nine months ended September 30 was as follows (in thousands):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
	Cost of revenues	$	59	$	10	$	103	$	36
	Selling, general and administrative		348		205		1,529		679
	Research and development		84		85		261		255
	Total stock-based compensation	$	491	$	300	$	1,893	$	970
	On May 17, 2013, the Company commenced an offer (the “Exchange Offer”) to its employees and directors to exchange certain outstanding options to purchase shares of the Company’s common stock granted under the Company’s Amended and Restated 2000 Stock Option and Incentive Plan, as amended (the “2000 Plan”), on a one-for-one basis, for replacement options to purchase shares of common stock, to be granted under the Company’s 2000 Plan (the “Option Exchange”). All outstanding options under the 2000 Plan granted to employees and directors prior to January 1, 2013, whether or not vested, were eligible for the Option Exchange (“Eligible Options”). Eligible Options included those options with time-based vesting provisions (“Time-Based Eligible Options”) and those options with performance-based vesting provisions tied to the achievement of certain quarterly revenue targets by the Company’s Brick Business Unit (“Performance-Based Eligible Options”). Options for the purchase of shares of common stock of the Company’s subsidiaries, VI Chip Corporation and Picor Corporation, were not eligible for the Option Exchange.
	Pursuant to the Exchange Offer, which expired June 17, 2013 (the “Offer Expiration Date”), 638 eligible participants tendered, and the Company accepted for exchange, options to purchase an aggregate of 1,531,077 shares of the Company’s common stock, representing approximately 91% of Eligible Options. Upon acceptance, the tendered options were cancelled, and the Company granted an equivalent number of new options (the “Replacement Options”) under the 2000 Plan. All Replacement Options vest over five years, have a 10 year term, and have terms substantially similar to other time-based vesting options awarded under the 2000 Plan. Replacement Options granted in exchange for Time-Based Eligible Options have an exercise price equal to $6.29 (being 120% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date). Replacement Options granted in exchange for Performance-Based Eligible Options have an exercise price equal to (i) $6.29 (being 120% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date) with respect to Replacement Options that vest on or prior to the first anniversary of the Offer Expiration Date; (ii) $7.34 (being 140% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date) with respect to Replacement Options that vest after the first anniversary of the Offer Expiration Date but on or prior to the second anniversary of the Offer Expiration Date; (iii) $8.38 (being 160% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date) with respect to Replacement Options that vest after the second anniversary of the Offer Expiration Date but on or prior to the third anniversary of the Offer Expiration Date; (iv) $9.43 (being 180% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date) with respect to Replacement Options that vest after the third anniversary of the Offer Expiration Date but on or prior to the fourth anniversary of the Offer Expiration Date; and (v) $10.48 (being 200% of the last reported sale price per share of the Company’s common stock on the NASDAQ on the Offer Expiration Date) with respect to Replacement Options that vest after the fourth anniversary of the Offer Expiration Date.
	For financial reporting purposes, the exchange of Time-Based Eligible Options for Replacement Options was considered a modification of both the exercise price and the vesting terms of the cancelled options. The accounting for these modifications results in total incremental expense of approximately $365,000, which, combined with the remaining unrecognized expense from the original grant date value of approximately $318,000, will be recognized over the associated service period (i.e., the five year vesting period) for each new vesting tranche. Because the Company had not previously recorded stock-based compensation expense for the Performance-Based Eligible Options, as the Company determined it was not probable the Brick Business Unit would meet the revenue targets required to trigger vesting of such options, the exchange of Replacement Options for Performance-Based Eligible Options has been accounted for as the grant of new options as of June 17, 2013, the Offer Expiration Date. As referenced above, because these Replacement Options have five different exercise prices (i.e., an increasing exercise price for each of the five different vesting periods, each with a different term to expiration), the value of such Replacement Options, calculated using the Black-Scholes methodology, was based on the assumption each vesting tranche represented a distinct instrument. The resulting total expense of approximately $2,300,000 will be recognized over the associated service period for each vesting tranche, as if the grant were, in substance, five grants of distinct instruments with different exercise prices and different, sequentially shorter, terms to expiration. The unrecognized compensation expense for these Replacement Options was approximately $2,047,000 as of September 30, 2013.
	Under the retirement provisions of the 2000 Plan and the option agreements applicable to the Replacement Options, the Company records all stock-based compensation expense for an option grant by the earlier of (a) the end of the associated service period (i.e., the vesting period) or (b) by age 62.5 of the employee or director to whom the options were awarded. Because of the age of certain recipient employees and directors, a number of Replacement Options granted were subject to immediate recognition of the associated total stock-based compensation expense. Accordingly, as a result of the Option Exchange, the Company recorded stock-based compensation expense during the second quarter of 2013 of approximately $625,000, of which approximately $450,000 was the result of immediate expense recognition due to the age of the recipient employee or director.
	Separate from the Option Exchange, on May 14, 2013, the Company awarded options to purchase, at an exercise price of $5.35 per share, an aggregate of 150,000 shares of common stock, under the 2000 Plan, to certain officers. In addition, on June 21, 2013, the Company awarded options to purchase, at an exercise price of $5.67 per share, an aggregate of 70,552 shares of common stock, under the 2000 Plan, to directors as a component of their annual compensation. The total stock-based compensation expense recognized during the second quarter of 2013 for these awards was approximately $208,000, of which approximately $190,000 was the result of immediate expense recognition due to the age of the recipient officer or director.
	During the third quarter of 2010, the Company granted an aggregate of 1,243,750 Performance-Based Eligible Options. Based on the final results of the Option Exchange, a total of 66,000 of these Performance-Based Eligible Options remain outstanding as of September 30, 2013. Under the accounting rules for performance-based awards, the Company is required to assess, on an ongoing basis, the probability of whether the performance criteria will be achieved. If and when achievement is deemed probable, the Company will begin to recognize the associated compensation expense for the remaining stock options over the relevant performance period. As of September 30, 2013, the Company determined it was not probable the revenue targets could be achieved and, accordingly, has not recorded any compensation expense relating to these options since the grant date. The unrecognized compensation expense of these performance-based options was approximately $414,000 as of September 30, 2013.
	On December 31, 2010, the Company granted 2,984,250 non-qualified stock options under the VI Chip 2007 Stock Option and Incentive Plan with performance-based vesting provisions tied to achievement of certain margin targets by the VI Chip subsidiary. As of December 31, 2010, the Company determined it was probable the margin targets could be achieved and, accordingly, began recording stock-based compensation expense relating to these options beginning January 1, 2011. This determination remains the same as of September 30, 2013 and, accordingly, expense has been recorded through that date. The unrecognized compensation expense for these performance-based options was approximately $777,000 as of September 30, 2013.

Net_Income_Loss_per_Share

Net Income (Loss) per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Net Income (Loss) per Share	5. Net Income (Loss) per Share
	The following table sets forth the computation of basic and diluted income (loss) per share for the three and nine months ended September 30 (in thousands, except per share amounts):
			Three Months Ended					Nine Months Ended
			September 30,					September 30,
			2013			2012		2013			2012
	Numerator:
	Net income (loss) attributable to Vicor Corporation		$	(932	)	$	191	$	(10,538	)	$	737
	Denominator:
	Denominator for basic income (loss) per share-weighted average shares (1)			38,538			41,811		39,414			41,811
	Effect of dilutive securities:
	Employee stock options (2)			—			4		—			7
	Denominator for diluted income (loss) per share – adjusted weighted-average shares and assumed conversions			38,538			41,815		39,414			41,818
	Basic income (loss) per share		$	(0.02	)	$	—	$	(0.27	)	$	0.02
	Diluted income (loss) per share		$	(0.02	)	$	—	$	(0.27	)	$	0.02
	-1	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding.
	-2	Options to purchase 1,142,576 and 1,098,473 shares of Common Stock for the three and nine months ended September 30, 2013, respectively, were not included in the calculation of net loss per share as the effect would have been antidilutive. Options to purchase 550,655 and 490,585 shares of Common Stock for the three and nine months ended September 30, 2012, respectively, were not included in the computation of diluted income per share because the effect would be antidilutive.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2013
Inventory Disclosure [Abstract]
Inventories	6. Inventories
	Inventories are valued at the lower of cost (determined using the first-in, first-out method) or net realizable value. Fixed production overhead is allocated to the inventory cost per unit based on the normal capacity of the production facilities. Abnormal production costs, including fixed cost variances from normal production capacity, if any, are charged to cost of revenues in the period incurred. All shipping and handling costs incurred in connection with the sale of products are included in cost of revenues.
	The Company provides reserves for inventories estimated to be excess, obsolete or unmarketable. The Company’s estimation process for assessing net realizable value is based upon its known backlog, projected future demand and expected market conditions. If the Company’s estimated demand and/or market expectation were to change or if product sales were to decline, the Company’s estimation process may cause larger inventory reserves to be recorded, resulting in larger charges to cost of revenues.
	Inventories were as follows (in thousands):
		September 30, 2013			December 31, 2012
	Raw materials	$	27,022		$	28,362
	Work-in-process		3,266			2,707
	Finished goods		5,898			6,535
			36,186			37,604
	Inventory reserves		(8,199	)		(7,649	)
	Net balance	$	27,987		$	29,955

Other_Investments

Other Investments	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]
Other Investments	7. Other Investments
	The Company’s gross investment in non-voting convertible preferred stock of Great Wall Semiconductor Corporation (“GWS”) totaled $5,000,000 as of September 30, 2013, and December 31, 2012, giving the Company an approximately 27% ownership interest in GWS. GWS and its subsidiary design and sell semiconductors, conduct research and development activities, develop and license patents, and litigate against those who infringe upon its patented technologies. A director of the Company is the founder, Chairman of the Board, President and Chief Executive Officer (“CEO”), as well as the majority voting shareholder, of GWS. The Company and GWS are parties to an intellectual property cross-licensing agreement, a license agreement and two supply agreements under which the Company purchases certain components from GWS. Purchases from GWS totaled approximately $831,000 and $1,210,000 for the nine months ended September 30, 2013, and 2012, respectively.
	The Company accounts for its investment in GWS under the equity method of accounting. The Company has determined that, while GWS is a variable interest entity, the Company is not the primary beneficiary. The key factors in the Company’s assessment were that the CEO of GWS has: (i) the power to direct the activities of GWS that most significantly impact its economic performance, and (ii) has an obligation to absorb losses or the right to receive benefits from GWS, respectively, that could potentially be significant to GWS.
	There was no allocation of equity method income (loss) for the nine months ended September 30, 2013 and 2012, as GWS incurred a net loss in each period. The balance in the Company’s net investment in GWS was zero as of September 30, 2013, and December 31, 2012.

Severance_Charges

Severance Charges	9 Months Ended
	Sep. 30, 2013
Restructuring And Related Activities [Abstract]
Severance Charges	8. Severance Charges
	In February 2013, the Company initiated and completed workforce reductions. As a result, the Company recorded a pre-tax charge of $1,361,000 in the first quarter of 2013 for the cost of severance and other employee-related costs involving cash payments based on each employee’s respective length of service. These charges were recorded as “Severance charges” in the Condensed Consolidated Statement of Operations. The related liability is presented as “Accrued severance charges” in the Condensed Consolidated Balance Sheets.
	A summary of the activity related to the severance charges, by segment, for the nine months ended September 30, 2013 is as follows (in thousands):
		BBU			VI Chip			Total
	Balance as of December 31, 2012	$	—		$	—		$	—
	Charges		1,123			238			1,361
	Payments		(201	)		(81	)		(282	)
	Balance as of March 31, 2013		922			157			1,079
	Payments		(417	)		(51	)		(468	)
	Balance as of June 30, 2013		505			106			611
	Payments		(268	)		(94	)		(362	)
	Balance as of September 30, 2013	$	237		$	12		$	249

Product_Warranties

Product Warranties	9 Months Ended
	Sep. 30, 2013
Guarantees [Abstract]
Product Warranties	9. Product Warranties
	The Company generally offers a two-year warranty for all of its products. The Company provides for the estimated cost of product warranties at the time product revenue is recognized. Factors that affect the Company’s warranty reserves include the number of units sold, historical and anticipated rates of warranty returns, and the cost per return. The Company assesses the adequacy of the warranty reserves and adjusts the amounts as necessary. Warranty obligations are included in “Accrued expenses” in the accompanying Condensed Consolidated Balance Sheets.
	Product warranty activity for the three and nine months ended September 30, was as follows (in thousands):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Balance at the beginning of the period	$	329		$	461		$	364		$	572
	Accruals for warranties for products sold in the period		127			161			228			379
	Fulfillment of warranty obligations		(110	)		(133	)		(220	)		(430	)
	Revisions of estimated obligations		1			(8	)		(25	)		(40	)
	Balance at the end of the period	$	347		$	481		$	347		$	481

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity
	Under a tender offer completed on April 22, 2013, the Company purchased 1,341,575 shares of Common Stock for an aggregate cost of $6,708,000.
	Under a previous tender offer completed on March 7, 2013, the Company purchased 1,931,513 shares of Common Stock for an aggregate cost of $10,392,000.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes
	The tax provision is based on the estimated annual effective tax rate for the year, which includes estimated federal, state and foreign income taxes (benefit) on the Company’s projected annual pre-tax income (loss) and estimated federal and state income taxes for certain noncontrolling interest subsidiaries that are not part of the Company’s consolidated income tax returns.
	The (benefit) provision for income taxes and the effective income tax rate for the three and nine months ended September 30, were as follows (in thousands):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(Benefit) provision for income taxes	$	(406	)	$	86		$	(6,337	)	$	809
	Effective income tax rate		(31.1	%)		23.5	%		(37.7	%)		48.3	%
	For the three months and nine months ended September 30, 2013, a net income tax benefit was recorded primarily due to an increase in net federal deferred tax assets not covered by a valuation allowance, a potential net operating loss carryback for federal income tax purposes and the recognition of a benefit from the federal research tax credit for 2012 of $549,000, as a discrete item in the first quarter of 2013. The federal research tax credit for 2012 and 2013 was extended on January 2, 2013 pursuant to the American Taxpayer Relief Act of 2012. The Company recorded a provision for income taxes for the three months and nine months ended September 30, 2012 based on the Company’s projecting annual pre-tax income at that time. The effective income tax rate for the nine months ended September 30, 2012 was higher than statutory tax rates due to higher state tax expense from separate company calculations based off expected taxable income from Vicor-only operations that could not be offset by operating losses in other business segments. In addition, the Company did not have the ability to generate federal research and development credits as those credits had yet to be extended by the United States Congress for 2012.
	As of September 30, 2013, the Company has a valuation allowance of approximately $8,759,000 primarily against certain state deferred tax assets, for which realization cannot be considered more likely than not at this time. Such deferred tax assets principally relate to tax net operating loss and credit carryforwards in certain state tax jurisdictions for which sufficient taxable income for utilization cannot be projected at this time, which may result in the net operating losses or credits or both potentially expiring without being utilized due to shorter carryforward periods. Management assesses the need for the valuation allowance on a quarterly basis. In assessing the need for a valuation allowance, the Company considers all positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies, and income in the carryback period. If and when management determines the valuation allowance should be released, the adjustment would result in a tax benefit in the Consolidated Statements of Operations and may include a portion to be accounted for through “Additional paid-in capital”, a component of Stockholders’ Equity. The amount of the tax benefit to be recorded in a particular quarter could be material. Management believes it is more likely than not the Company’s net federal deferred tax assets of approximately $11,293,000 as of September 30, 2013 will be realized, based upon its assessment of all available evidence, both positive and negative. In light of recent operating losses, management is continuing to closely monitor the available positive and negative evidence on a quarterly basis to determine if the more likely than not standard will continue to be met. If management determines that the more likely than not standard will not be met, then the valuation allowance may need to be increased, and such adjustment in a particular quarter could be material.
	In August 2013, the Company received notice from the Internal Revenue Service that its federal corporate tax returns for the tax years 2010 and 2011 had been selected for audit. The audit has commenced, but is in the early stages. There are no other income tax audits currently in process.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies
	At September 30, 2013, the Company had approximately $1,220,000 of capital expenditure commitments.
	On January 28, 2011, SynQor, Inc. (“SynQor”) filed a complaint for patent infringement against Ericsson, Inc. (“Ericsson”), Cisco Systems, Inc. (“Cisco”) and the Company in U.S. District Court for the Eastern District of Texas (“the Texas Action”). This immediately followed a complaint filed by the Company on January 26, 2011, in U.S. District Court for the District of Massachusetts, in which the Company sought a declaratory judgment that its bus converter products do not infringe any valid claim of certain of SynQor’s U.S. patents, and that the claims of those patents are invalid. With respect to the Company, SynQor’s complaint alleges the Company’s products, including, but not limited to, unregulated bus converters used in intermediate bus architecture power supply systems, infringe certain SynQor patents. SynQor seeks, among other items, an injunction against further infringement and an award of unspecified compensatory and enhanced damages, interest, costs and attorney fees. On February 8, 2011, SynQor filed a motion for preliminary injunction seeking an order enjoining the Company from manufacturing, using, selling, and offering for sale in the United States and/or importing into the United States certain identified unregulated bus converters, as well as any other bus converters not significantly different from those products. On February 17, 2011, the Company withdrew its Massachusetts action without prejudice to allow the litigation to proceed in Texas. On May 16, 2011, SynQor announced it was withdrawing its motion for preliminary injunction against the Company. On September 16, 2011, the U.S. District Court for the Eastern District of Texas issued an order setting a trial date of July 7, 2014. On September 20, 2011, SynQor filed an amended complaint in the Texas Action. The amended complaint repeated the allegations of patent infringement against the Company contained in SynQor’s original complaint, and included additional patent infringement allegations with respect to U.S. Patent No. 8,023,290 (“290 patent”), which was issued on that day. As with SynQor’s original complaint, the amended complaint alleged that the Company’s products, including but not limited to the Company’s unregulated bus converters used in intermediate bus architecture power supply systems, infringed the asserted patents. On October 4, 2011, the Company filed an answer and counterclaims to SynQor’s amended complaint, in which the Company alleges the 290 patent is unenforceable because it was procured through inequitable conduct before the U.S. Patent and Trademark Office and seeks damages against SynQor for SynQor’s unfair and deceptive trade practices and tortious interference with prospective economic advantage in connection with SynQor’s allegations of patent infringement against the Company. The Company does not believe any of its products, including its unregulated bus converters, infringe any valid claim of the asserted SynQor patents, either alone or when used in an intermediate bus architecture implementation. The Company believes SynQor’s claims lack merit and, therefore, continues to vigorously defend itself against SynQor’s patent infringement allegations.
	In addition, the Company is involved in certain other litigation and claims incidental to the conduct of its business. While the outcome of lawsuits and claims against the Company cannot be predicted with certainty, management does not expect any current litigation or claims to have a material adverse impact on the Company’s financial position or results of operations.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	13. Segment Information
	The Company has organized its business segments according to its key product lines. The Brick Business Unit segment (“BBU”) designs, develops, manufactures and markets the Company’s modular power converters and configurable products, and also includes the operations of the Company’s Westcor division, the six entities comprising Vicor Custom Power, and the BBU operations of Vicor Japan Company, Ltd. (“VJCL”). The VI Chip segment includes VI Chip Corporation, which designs, develops, manufactures and markets the Company’s factorized power architecture (“FPA”) products. The VI Chip segment also includes the VI Chip business conducted through VJCL. The Picor segment includes Picor Corporation, which designs, develops, manufactures and markets integrated circuits and related products for use in a variety of power management and power system applications. Picor develops these products to be sold as part of the Company’s products or to third parties for separate applications.
	The Company’s chief operating decision maker evaluates performance and allocates resources based on segment revenues and segment operating income (loss). The operating income (loss) for each segment includes selling, general and administrative and research and development expenses directly attributable to the segment. Certain of the Company’s indirect overhead costs, which include corporate selling, general and administrative expenses, are allocated among the segments based upon an estimate of costs associated with each segment. Assets allocated to each segment are based upon specific identification of such assets, which include accounts receivable, inventories, fixed assets and certain other assets. The Corporate segment consists of those operations and assets shared by all segments. The costs of certain centralized executive and administrative functions are recorded in this segment, as are certain shared assets, most notably cash and cash equivalents, deferred tax assets, long-term investments, the Company’s facilities in Massachusetts, real estate and other assets. The Company’s accounting policies and method of presentation for segments are consistent with that used throughout the Condensed Consolidated Financial Statements.
	The following table provides significant segment financial data as of and for the three months ended September 30, (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations (1)			Total
	2013:00:00
	Net revenues		$	42,331	$	12,457		$	2,836		$	—		$	(2,533	)	$	55,091
	Income (loss) from operations			5,162		(5,555	)		(696	)		(266	)		—			(1,355	)
	Total assets			119,739		19,898			4,345			98,614			(61,718	)		180,878
	Depreciation and amortization			1,296		760			96			375			—			2,527
	2012:00:00
	Net revenues		$	45,753	$	7,487		$	2,206		$	—		$	(2,498	)	$	52,948
	Income (loss) from operations			7,903		(6,620	)		(813	)		(174	)		—			296
	Total assets			94,532		22,085			5,245			129,444			(41,507	)		209,799
	Depreciation and amortization			1,267		885			103			371			—			2,626
	The following table provides significant segment financial data as of and for the nine months ended September 30, (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations			Total
	2013:00:00
	Net revenues		$	120,743	$	22,503		$	7,426		$	—		$	(6,770	)	$	143,902
	Income (loss) from operations			9,752		(23,142	)		(2,711	)		(732	)		—			(16,833	)
	Total assets			119,739		19,898			4,345			98,614			(61,718	)		180,878
	Depreciation and amortization			3,773		2,468			315			999			—			7,555
	2012:00:00
	Net revenues		$	136,510	$	31,425		$	7,320		$	—		$	(7,172	)	$	168,083
	Income (loss) from operations			22,361		(18,424	)		(1,926	)		(542	)		—			1,469
	Total assets			94,532		22,085			5,245			129,444			(41,507	)		209,799
	Depreciation and amortization			3,771		2,677			309			1,113			—			7,870
	-1	The elimination for net revenues is principally related to inter-segment revenues of Picor to BBU and VI Chip and for inter-segment revenues of VI Chip to BBU. The elimination for total assets is principally related to inter-segment accounts receivable due to BBU for the funding of VI Chip and Picor operations.

Impact_of_Recently_Issued_Acco

Impact of Recently Issued Accounting Standards	9 Months Ended
	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]
Impact of Recently Issued Accounting Standards	14. Impact of Recently Issued Accounting Standards
	In July 2013, the Financial Accounting Standards Board (“FASB”) issued an amendment to the accounting guidance related to the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss or a tax credit carryforward exists. The guidance requires an unrecognized tax benefit to be presented as a decrease in a deferred tax asset where a net operating loss, a similar tax loss, or a tax credit carryforward exists and certain criteria are met. This guidance is effective prospectively for annual and interim reporting periods beginning after December 15, 2013. The Company is currently evaluating the potential impact of the adoption of this guidance on its consolidated financial statements.
	Effective January 1, 2013, the Company adopted new accounting guidance related to disclosures about offsetting assets and liabilities. The new accounting guidance amends ASC 210, Balance Sheet, to converge the presentation of offsetting assets and liabilities between U.S. Generally Accepted Accounting Principles (“U.S. GAAP”) and International Financial Reporting Standards (“IFRS”) and requires entities disclose both gross information and new information about both instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an agreement similar to a master netting arrangement. The adoption of this new guidance did not impact the Company’s financial position or results of operations.
	Effective January 1, 2013, the Company adopted new accounting guidance for the reporting of amounts reclassified out of accumulated other comprehensive income. This guidance requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required under U.S. GAAP to be reclassified in its entirety to net income. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under U.S. GAAP that provide additional detail about those amounts. The adoption of this new guidance did not materially impact the Company’s financial position or results of operations.

LongTerm_Investments_Tables

Long-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following is a summary of available-for-sale securities (in thousands):
					Gross			Gross		Estimated
					Unrealized			Unrealized		Fair
	September 30, 2013	Cost			Gains			Losses		Value
	Failed Auction Securities	$	6,000		$	—		$	1,018	$	4,982
	Brokered certificates of deposit		1,010			8			—		1,018
	Certificate of deposit		231			—			—		231
		$	7,241		$	8		$	1,018	$	6,231
					Gross			Gross		Estimated
					Unrealized			Unrealized		Fair
	December 31, 2012	Cost			Gains			Losses		Value
	Failed Auction Securities	$	6,100		$	—		$	1,121	$	4,979
	Brokered certificates of deposit		1,280			12			—		1,292
	Certificates of deposit		465			—			—		465
		$	7,845		$	12		$	1,121	$	6,736
Amortized Cost and Estimated Fair Value of Available-for-Sale Securities	The amortized cost and estimated fair value of available-for-sale securities on September 30, 2013, by contractual maturities, are shown below (in thousands):
					Estimated
		Cost			Fair Value
	Due in one year or less	$	611		$	612
	Due in two to ten years		630			637
	Due in ten to twenty years		—			—
	Due in twenty to forty years		6,000			4,982
		$	7,241		$	6,231
Roll Forward of Credit Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities	The following table represents a roll forward of the activity related to the credit loss recognized in earnings on available-for-sale auction rate securities held by the Company for the nine months ended September 30 (in thousands):
		2013			2012
	Balance at the beginning of the period	$	317		$	308
	Additions for the amount related to credit loss for which other-than-temporary impairment was not previously recognized		85			—
	Reduction for security sold during the period		(7	)		(16	)
	Balance at the end of the period	$	395		$	292

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on Recurring Basis	Assets measured at fair value on a recurring basis include the following as of September 30, 2013 (in thousands):
		Using
		Quoted Prices			Significant			Significant		Total Fair
		in Active			Other			Unobservable		Value as of
		Markets			Observable			Inputs		September 30, 2013
		(Level 1)			Inputs			(Level 3)
					(Level 2)
	Cash Equivalents:
	Money market funds	$	12,485		$	—		$	—	$	12,485
	Long-term investments:
	Failed Auction Securities		—			—			4,982		4,982
	Brokered certificates of deposit		—			1,018			—		1,018
	Certificate of deposit		231			—			—		231
Quantitative Information about Level 3 Fair Value Measurements	Quantitative information about Level 3 fair value measurements as of September 30, 2013 are as follows (dollars in thousands):
								Range
					Valuation		Unobservable	(Weighted
		Fair Value			Technique		Input	Average)
	Failed Auction Securities	$	4,982		Discounted		Cumulative probability of earning the maximum rate until maturity	0.01% - 0.05%
					cash flow			-0.03%
							Cumulative probability of principal return prior to maturity	74.24% - 95.60%
								-84.92%
							Cumulative probability of default	4.39% - 25.71%
								-15.05%
							Liquidity risk premium	5.00% - 5.00%
								-5.00%
							Recovery rate in default	40.00% - 40.00%
								-40.00%
Change in Estimated Fair Values Calculated for Assets Valued on Recurring Basis Utilizing Level 3 Inputs	The following table summarizes the change in the estimated fair values calculated for those assets valued on a recurring basis utilizing Level 3 inputs (i.e., the Failed Auction Securities) for the nine months ended September 30, 2013 (in thousands):
	Balance at the beginning of the period	$	4,979
	Redemptions, at par		(100	)
	Credit loss on available-for-sale securities included in Other income (expense), net		(78	)
	Unrealized gain included in Other comprehensive income (loss)		181
	Balance at the end of the period	$	4,982

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense	value of stock option awards as of their grant date. Stock-based compensation expense for the three and nine months ended September 30 was as follows (in thousands):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
	Cost of revenues	$	59	$	10	$	103	$	36
	Selling, general and administrative		348		205		1,529		679
	Research and development		84		85		261		255
	Total stock-based compensation	$	491	$	300	$	1,893	$	970

Net_Income_Loss_per_Share_Tabl

Net Income (Loss) per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Computation of Basic and Diluted Income Per Share	The following table sets forth the computation of basic and diluted income (loss) per share for the three and nine months ended September 30 (in thousands, except per share amounts):
			Three Months Ended					Nine Months Ended
			September 30,					September 30,
			2013			2012		2013			2012
	Numerator:
	Net income (loss) attributable to Vicor Corporation		$	(932	)	$	191	$	(10,538	)	$	737
	Denominator:
	Denominator for basic income (loss) per share-weighted average shares (1)			38,538			41,811		39,414			41,811
	Effect of dilutive securities:
	Employee stock options (2)			—			4		—			7
	Denominator for diluted income (loss) per share – adjusted weighted-average shares and assumed conversions			38,538			41,815		39,414			41,818
	Basic income (loss) per share		$	(0.02	)	$	—	$	(0.27	)	$	0.02
	Diluted income (loss) per share		$	(0.02	)	$	—	$	(0.27	)	$	0.02
	-1	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding.
	-2	Options to purchase 1,142,576 and 1,098,473 shares of Common Stock for the three and nine months ended September 30, 2013, respectively, were not included in the calculation of net loss per share as the effect would have been antidilutive. Options to purchase 550,655 and 490,585 shares of Common Stock for the three and nine months ended September 30, 2012, respectively, were not included in the computation of diluted income per share because the effect would be antidilutive.

Inventories_Tables

Inventories (Tables)	9 Months Ended
	Sep. 30, 2013
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories were as follows (in thousands):
		September 30, 2013			December 31, 2012
	Raw materials	$	27,022		$	28,362
	Work-in-process		3,266			2,707
	Finished goods		5,898			6,535
			36,186			37,604
	Inventory reserves		(8,199	)		(7,649	)
	Net balance	$	27,987		$	29,955

Severance_Charges_Tables

Severance Charges (Tables)	9 Months Ended
	Sep. 30, 2013
Restructuring And Related Activities [Abstract]
A Summary of Activity Related to Severance Charges	A summary of the activity related to the severance charges, by segment, for the nine months ended September 30, 2013 is as follows (in thousands):
		BBU			VI Chip			Total
	Balance as of December 31, 2012	$	—		$	—		$	—
	Charges		1,123			238			1,361
	Payments		(201	)		(81	)		(282	)
	Balance as of March 31, 2013		922			157			1,079
	Payments		(417	)		(51	)		(468	)
	Balance as of June 30, 2013		505			106			611
	Payments		(268	)		(94	)		(362	)
	Balance as of September 30, 2013	$	237		$	12		$	249

Product_Warranties_Tables

Product Warranties (Tables)	9 Months Ended
	Sep. 30, 2013
Guarantees [Abstract]
Product Warranty Activity	Product warranty activity for the three and nine months ended September 30, was as follows (in thousands):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	Balance at the beginning of the period	$	329		$	461		$	364		$	572
	Accruals for warranties for products sold in the period		127			161			228			379
	Fulfillment of warranty obligations		(110	)		(133	)		(220	)		(430	)
	Revisions of estimated obligations		1			(8	)		(25	)		(40	)
	Balance at the end of the period	$	347		$	481		$	347		$	481

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Provision for Income Taxes and Effective Income Tax Rate	The (benefit) provision for income taxes and the effective income tax rate for the three and nine months ended September 30, were as follows (in thousands):
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
	(Benefit) provision for income taxes	$	(406	)	$	86		$	(6,337	)	$	809
	Effective income tax rate		(31.1	%)		23.5	%		(37.7	%)		48.3	%

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Significant of Segment Financial Data	The following table provides significant segment financial data as of and for the three months ended September 30, (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations (1)			Total
	2013:00:00
	Net revenues		$	42,331	$	12,457		$	2,836		$	—		$	(2,533	)	$	55,091
	Income (loss) from operations			5,162		(5,555	)		(696	)		(266	)		—			(1,355	)
	Total assets			119,739		19,898			4,345			98,614			(61,718	)		180,878
	Depreciation and amortization			1,296		760			96			375			—			2,527
	2012:00:00
	Net revenues		$	45,753	$	7,487		$	2,206		$	—		$	(2,498	)	$	52,948
	Income (loss) from operations			7,903		(6,620	)		(813	)		(174	)		—			296
	Total assets			94,532		22,085			5,245			129,444			(41,507	)		209,799
	Depreciation and amortization			1,267		885			103			371			—			2,626
	The following table provides significant segment financial data as of and for the nine months ended September 30, (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations			Total
	2013:00:00
	Net revenues		$	120,743	$	22,503		$	7,426		$	—		$	(6,770	)	$	143,902
	Income (loss) from operations			9,752		(23,142	)		(2,711	)		(732	)		—			(16,833	)
	Total assets			119,739		19,898			4,345			98,614			(61,718	)		180,878
	Depreciation and amortization			3,773		2,468			315			999			—			7,555
	2012:00:00
	Net revenues		$	136,510	$	31,425		$	7,320		$	—		$	(7,172	)	$	168,083
	Income (loss) from operations			22,361		(18,424	)		(1,926	)		(542	)		—			1,469
	Total assets			94,532		22,085			5,245			129,444			(41,507	)		209,799
	Depreciation and amortization			3,771		2,677			309			1,113			—			7,870
	-1	The elimination for net revenues is principally related to inter-segment revenues of Picor to BBU and VI Chip and for inter-segment revenues of VI Chip to BBU. The elimination for total assets is principally related to inter-segment accounts receivable due to BBU for the funding of VI Chip and Picor operations.

LongTerm_Investments_Additiona

Long-Term Investments - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Auction rate securities, par value	$7,241,000	$7,845,000
Minimum Period for which failed Auction Securities been in unrealized loss position	12 months
Fair value of Failed Auction Securities	6,231,000	6,736,000
Gross Unrealized Losses	1,018,000	1,121,000
Aggregate credit loss	395,000	317,000	292,000	308,000
Failed Auction Securities [Member]
Auction rate securities, par value	6,000,000	6,100,000
Interest rates auction time	28 days
Period for which Failed Auction Securities been in unrealized loss position	Exceeds 12 months
Fair value of Failed Auction Securities	4,982,000	4,979,000
Increase in fair value	103,000
Gross Unrealized Losses	1,018,000	1,121,000
Aggregate credit loss	395,000
Aggregate temporary impairment loss	623,000
Increased aggregate credit (losses) gains on Failed Auction Securities	$78,000

LongTerm_Investments_Summary_o

Long-Term Investments - Summary of Available-for-Sale Securities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cost	$7,241,000	$7,845,000
Gross Unrealized Gains	8,000	12,000
Gross Unrealized Losses	1,018,000	1,121,000
Estimated Fair Value	6,231,000	6,736,000
Failed Auction Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	6,000,000	6,100,000
Gross Unrealized Gains
Gross Unrealized Losses	1,018,000	1,121,000
Estimated Fair Value	4,982,000	4,979,000
Brokered Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	1,010,000	1,280,000
Gross Unrealized Gains	8,000	12,000
Gross Unrealized Losses
Estimated Fair Value	1,018,000	1,292,000
Certificate of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	231,000	465,000
Gross Unrealized Gains
Gross Unrealized Losses
Estimated Fair Value	$231,000	$465,000

LongTerm_Investments_Amortized

Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Cost	$611
Due in two to ten years, Cost	630
Due in ten to twenty years, Cost
Due in twenty to forty years, Cost	6,000
Total Cost	7,241	7,845
Due in one year or less, Estimated Fair Value	612
Due in two to ten years, Estimated fair Value	637
Due in ten to twenty years, Estimated Fair Value
Due in twenty to forty years, Estimated Fair Value	4,982
Estimated Fair Value	$6,231	$6,736

LongTerm_Investments_Roll_Forw

Long-Term Investments - Roll Forward of Credit Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Investments Debt And Equity Securities [Abstract]
Balance at the beginning of the period	$317	$308
Additions for the amount related to credit loss for which other-than-temporary impairment was not previously recognized	85
Reduction for security sold during the period	-7	-16
Balance at the end of the period	$395	$292

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$6,231	$6,736
Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	4,982	4,979
Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	1,018	1,292
Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	231	465
Recurring [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	4,982
Recurring [Member] | Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	1,018
Recurring [Member] | Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	231
Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	12,485
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	231
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	12,485
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	1,018
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	4,982
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Certificate of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Percent of credit loss	6.40%
Rate of return required	5.00%
Estimated timeframe for auctions of securities minimum	3 years
Estimated timeframe for auctions of securities maximum	5 years
Percentage of liquidity risk premium	5.00%
Increase or decrease in the liquidity risk premium	1.00%
Increase or decrease, respectively, the fair value of the Failed Auction Securities	$300,000

Fair_Value_Measurements_Quanti

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Detail) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

In Thousands, unless otherwise specified

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Failed Auction Securities [Member]

Cumulative Probability of Earning Maximum Rate Until Maturity [Member]

Cumulative Probability of Principal Return Prior to Maturity [Member]

Cumulative Probability of Default [Member]

Liquidity Risk Premium [Member]

Recovery Rate in Default [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Significant Unobservable Inputs (Level 3) [Member]

Cumulative Probability of Earning Maximum Rate Until Maturity [Member]

Cumulative Probability of Principal Return Prior to Maturity [Member]

Cumulative Probability of Default [Member]

Liquidity Risk Premium [Member]

Recovery Rate in Default [Member]

Cumulative Probability of Earning Maximum Rate Until Maturity [Member]

Cumulative Probability of Principal Return Prior to Maturity [Member]

Cumulative Probability of Default [Member]

Liquidity Risk Premium [Member]

Recovery Rate in Default [Member]

Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]

Estimated Fair Value

$6,231

$6,736

$4,982

Valuation Technique

Discounted cash flow

Unobservable Input

Cumulative probability of earning the maximum rate until maturity

Cumulative probability of principal return prior to maturity

Cumulative probability of default

Liquidity risk premium

Recovery rate in default

Weighted Average Interest Rate

0.03%

84.92%

15.05%

5.00%

40.00%

0.01%

74.24%

4.39%

5.00%

40.00%

0.05%

95.60%

25.71%

5.00%

40.00%

Fair_Value_Measurements_Change

Fair Value Measurements - Change in Estimated Fair Values Calculated for Assets Valued on Recurring Basis Utilizing Level 3 Inputs (Detail) (Recurring [Member], Significant Unobservable Inputs (Level 3) [Member], Failed Auction Securities [Member], USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at the beginning of the period	$4,979
Redemptions, at par	-100
Credit loss on available-for-sale securities included in Other income (expense), net	-78
Unrealized gain included in Other comprehensive income (loss)	181
Balance at the end of the period	$4,982

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$491	$300	$1,893	$970
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	59	10	103	36
Selling, General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	348	205	1,529	679
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$84	$85	$261	$255

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

9 Months Ended

Jun. 17, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2010

Sep. 30, 2010

14-May-13

Jun. 21, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Participant

Two Thousand Plan [Member]

Two Thousand Plan [Member]

Two Thousand Plan [Member]

Two Thousand Plan [Member]

Performance Based Options [Member]

Time Based Option [Member]

Vicor Corporation Amended and Restated 2000 Stock Option and Incentive Plan, with Performance-Based Vesting Provisions [Member]

Vi Chip 2007 Stock Option and Incentive Plan with Performance-Based Vesting Provisions [Member]

Tranches One [Member]

Tranches One [Member]

Tranches Two [Member]

Tranches Three [Member]

Tranche Four [Member]

Tranche Five [Member]

Employees and Directors [Member]

Performance Based Options [Member]

Time Based Option [Member]

Performance Based Options [Member]

Performance Based Options [Member]

Performance Based Options [Member]

Performance Based Options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Eligible participants

638

Options to purchase shares of Common Stock

1,531,077

Percentage of common stock

91.00%

Replacement option vesting period

5 years

Replacement option expiration period

10 years

Time-Based eligible Option exercise price

$6.29

$6.29

Common stock exercise price percentage

120.00%

120.00%

140.00%

160.00%

180.00%

200.00%

Common stock sales price

$6.29

$7.34

$8.38

$9.43

$10.48

Incremental expenses

$365,000

$208,000

$625,000

Unrecognized compensation expense

318,000

318,000

2,047,000

414,000

777,000

Aggregate expenses

491,000

300,000

1,893,000

970,000

2,300,000

Age of employees

62 years 6 months

Immediate expense recognition

$190,000

$450,000

Exercise price of options awarded

$5.35

$5.67

Common stock options awarded

150,000

70,552

Non-qualified stock options

2,984,250

1,243,750

66,000

Net_Income_Loss_per_Share_Comp

Net Income (Loss) per Share - Computation of Basic and Diluted Income Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net income (loss) attributable to Vicor Corporation	($932)	$191	($10,538)	$737
Denominator:
Denominator for basic income (loss) per share-weighted average shares	38,538	41,811	39,414	41,811
Effect of dilutive securities:
Employee stock options		4		7
Denominator for diluted income (loss) per share - adjusted weighted-average shares and assumed conversions	38,538	41,815	39,414	41,818
Basic income (loss) per share	($0.02)		($0.27)	$0.02
Diluted income (loss) per share	($0.02)		($0.27)	$0.02

Net_Income_Loss_per_Share_Comp1

Net Income (Loss) per Share - Computation of Basic and Diluted Income Per Share (Parenthetical) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Options to purchase shares of Common Stock not included in the computation of diluted income per share	1,142,576	550,655	1,098,473	490,585

Inventories_Summary_of_Invento

Inventories - Summary of Inventories (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$27,022	$28,362
Work-in-process	3,266	2,707
Finished goods	5,898	6,535
Inventory, gross	36,186	37,604
Inventory reserves	-8,199	-7,649
Net balance	$27,987	$29,955

Other_Investments_Additional_I

Other Investments - Additional Information (Detail) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Variable Interest Entity [Line Items]
Ownership interest in investment	27.00%		27.00%
Purchase of components under agreement	$831,000	$1,210,000
Allocation of equity method income (loss)	0	0
Great Wall Semiconductor Corporation (GWS) [Member]
Variable Interest Entity [Line Items]
Investment in non-voting convertible preferred stock	0		0
Great Wall Semiconductor Corporation (GWS) [Member] | Convertible Preferred Stock [Member]
Variable Interest Entity [Line Items]
Investment in non-voting convertible preferred stock	$5,000,000		5,000,000

Severance_Charges_Additional_I

Severance Charges - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Restructuring And Related Activities [Abstract]
Total severance charges		$1,361		$1,361

Severance_Charges_A_Summary_of

Severance Charges - A Summary of Activity Related to Severance Charges (Detail) (USD $)	3 Months Ended			6 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Jun. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Severance And Other Charges [Line Items]
Restructuring Reserve, Beginning Balance	$611
Charges		1,361			1,361
Payments		-282		-468	-362
Restructuring Reserve, Ending Balance	249	1,079		611	249
BBU [Member]
Severance And Other Charges [Line Items]
Restructuring Reserve, Beginning Balance
Charges		1,123
Payments		-201		-417	-268
Restructuring Reserve, Ending Balance	237	922		505	237
VI Chip [Member]
Severance And Other Charges [Line Items]
Restructuring Reserve, Beginning Balance
Charges		238
Payments		-81		-51	-94
Restructuring Reserve, Ending Balance	$12	$157		$106	$12

Product_Warranties_Additional_

Product Warranties - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
Guarantees [Abstract]
Warranty period	2 years

Product_Warranties_Product_War

Product Warranties - Product Warranty Activity (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Guarantees [Abstract]
Balance at the beginning of the period	$329	$461	$364	$572
Accruals for warranties for products sold in the period	127	161	228	379
Fulfillment of warranty obligations	-110	-133	-220	-430
Revisions of estimated obligations	1	-8	-25	-40
Balance at the end of the period	$347	$481	$347	$481

Stockholders_Equity_Additional

Stockholders' Equity - Additional information (Detail) (USD $)	1 Months Ended		9 Months Ended
	Apr. 22, 2013	Mar. 07, 2013	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of shares accepted	1,341,575	1,931,513
Common stock for aggregate consideration	$6,708,000	$10,392,000
Tender offer expiration date			22-Apr-13

Income_Taxes_Provision_for_Inc

Income Taxes - Provision for Income Taxes and Effective Income Tax Rate (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
(Benefit) provision for income taxes	($406)	$86	($6,337)	$809
Effective income tax rate	-31.10%	23.50%	-37.70%	48.30%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Federal research tax credit		$549,000
Valuation allowance for state deferred tax assets	8,759,000
Net deferred tax assets	$11,293,000

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]
Capital expenditure commitments	$1,220,000

Segment_Information_Additional

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Entity
Segment Reporting [Abstract]
Number of entities comprising operating segment	6

Segment_Information_Significan

Segment Information - Significant of Segment Financial Data (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net revenues	$55,091	$52,948	$143,902	$168,083
Income (loss) from operations	-1,355	296	-16,833	1,469
Total assets	180,878	209,799	180,878	209,799	202,581
Depreciation and amortization	2,527	2,626	7,555	7,870
Operating Segments [Member] | BBU [Member]
Segment Reporting Information [Line Items]
Net revenues	42,331	45,753	120,743	136,510
Income (loss) from operations	5,162	7,903	9,752	22,361
Total assets	119,739	94,532	119,739	94,532
Depreciation and amortization	1,296	1,267	3,773	3,771
Operating Segments [Member] | VI Chip [Member]
Segment Reporting Information [Line Items]
Net revenues	12,457	7,487	22,503	31,425
Income (loss) from operations	-5,555	-6,620	-23,142	-18,424
Total assets	19,898	22,085	19,898	22,085
Depreciation and amortization	760	885	2,468	2,677
Operating Segments [Member] | Picor [Member]
Segment Reporting Information [Line Items]
Net revenues	2,836	2,206	7,426	7,320
Income (loss) from operations	-696	-813	-2,711	-1,926
Total assets	4,345	5,245	4,345	5,245
Depreciation and amortization	96	103	315	309
Operating Segments [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Net revenues
Income (loss) from operations	-266	-174	-732	-542
Total assets	98,614	129,444	98,614	129,444
Depreciation and amortization	375	371	999	1,113
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net revenues	-2,533	-2,498	-6,770	-7,172
Income (loss) from operations
Total assets	-61,718	-41,507	-61,718	-41,507
Depreciation and amortization