Vicor (VICR) 10-K 6 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Feb. 27, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	VICR
Entity Registrant Name	VICOR CORP
Entity Central Index Key	751978
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Public Float		$136,352,200
Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			26,916,279
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			11,758,218

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$55,187	$56,339
Short-term investments	270	463
Accounts receivable, less allowance of $183 in 2014 and $198 in 2013	28,431	27,683
Inventories, net	26,328	29,696
Deferred tax assets	107	131
Other current assets	3,155	4,212
Total current assets	113,478	118,524
Long-term investments, net	3,002	5,188
Property, plant and equipment, net	37,387	40,092
Other assets	1,675	1,836
Total assets	155,542	165,640
Current liabilities:
Accounts payable	7,932	8,677
Accrued compensation and benefits	8,663	8,055
Accrued expenses	3,178	2,841
Accrued severance charges	1,904	49
Income taxes payable	41	15
Deferred revenue	1,439	1,018
Total current liabilities	23,157	20,655
Long-term deferred revenue	637	974
Long-term income taxes payable	867	1,339
Deferred income taxes	329	335
Total liabilities	24,990	23,303
Commitments and contingencies (Note 15)
Vicor Corporation stockholders' equity:
Preferred Stock, $.01 par value, 1,000,000 shares authorized; no shares issued
Additional paid-in capital	171,901	169,474
Retained earnings	94,758	108,645
Accumulated other comprehensive loss	-471	-526
Treasury stock at cost: 11,671,486 shares in 2014 and 2013	-138,927	-138,927
Total Vicor Corporation stockholders' equity	127,772	139,176
Noncontrolling interest	2,780	3,161
Total equity	130,552	142,337
Total liabilities and equity	155,542	165,640
Class B Common Stock [Member]
Vicor Corporation stockholders' equity:
Common Stock	118	118
Total equity	118	118
Common Stock [Member]
Vicor Corporation stockholders' equity:
Common Stock	$393	$392

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Accounts receivable, allowance	$183	$198
Preferred Stock, par value	$0.01	$0.01
Preferred Stock, shares authorized	1,000,000	1,000,000
Preferred Stock, shares issued	0	0
Treasury stock, shares	11,671,486	11,671,486
Class B Common Stock [Member]
Common Stock, votes per share	10	10
Common Stock, par value	$0.01	$0.01
Common Stock, shares authorized	14,000,000	14,000,000
Common Stock, shares issued	11,758,218	11,758,218
Common Stock, shares outstanding	11,758,218	11,758,218
Common Stock [Member]
Common Stock, votes per share	1	1
Common Stock, par value	$0.01	$0.01
Common Stock, shares authorized	62,000,000	62,000,000
Common Stock, shares issued	38,580,480	38,453,439
Common Stock, shares outstanding	26,908,994	26,781,953

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net revenues	$225,731	$199,160	$218,507
Cost of revenues	128,611	117,681	126,856
Gross margin	97,120	81,479	91,651
Operating expenses:
Selling, general and administrative	68,197	60,737	55,655
Research and development	41,479	39,848	38,744
Severance and other charges	2,207	1,361
Impairment of goodwill			2,012
Gain from litigation-related settlement			-1,975
Total operating expenses	111,883	101,946	94,436
Loss from operations	-14,763	-20,467	-2,785
Other income (expense), net:
Total unrealized gains (losses) on available-for-sale securities, net	750	-54	511
Portion of gains recognized in other comprehensive income (loss)	-439	-24	-520
Net credit gains (losses) recognized in earnings	311	-78	-9
Other income (expense), net	-43	80	203
Total other income (expense), net	268	2	194
Loss before income taxes	-14,495	-20,465	-2,591
(Benefit) provision for income taxes	-425	3,039	1,207
Consolidated net loss	-14,070	-23,504	-3,798
Less: Net income (loss) attributable to noncontrolling interest	-183	136	279
Net loss attributable to Vicor Corporation	($13,887)	($23,640)	($4,077)
Net loss per common share attributable to Vicor Corporation:
Basic	($0.36)	($0.60)	($0.10)
Diluted	($0.36)	($0.60)	($0.10)
Shares used to compute net loss per common share attributable to Vicor Corporation:
Basic	38,569	39,195	41,811
Diluted	38,569	39,195	41,811

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Consolidated net loss	($14,070)		($23,504)		($3,798)
Foreign currency translation losses, net of tax benefit	-410	[1]	-496	[1]	-355	[1]
Unrealized gains on available-for-sale securities, net of tax	429	[2]	17	[2]	520	[2]
Other comprehensive income (loss)	19		-479		165
Consolidated comprehensive loss	-14,051		-23,983		-3,633
Less: Comprehensive income (loss) attributable to noncontrolling interest	-219		71		234
Comprehensive loss attributable to Vicor Corporation	($13,832)		($24,054)		($3,867)
[1]	Net of tax benefit of $0, $(378) and $(241) for 2014, 2013 and 2012, respectively.
[2]	The deferred tax assets associated with cumulative unrealized losses on available for sale securities are completely offset by a tax valuation allowance as of December 31, 2014, 2013, and 2012. Therefore, there is no income tax benefit recognized for the years ended December 31, 2014, 2013, and 2012.

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Foreign currency translation gains (losses), tax benefit	$0	($378)	($241)
Recognized income tax provision (benefit)	$0	$0	$0

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities:
Consolidated net loss	($14,070)	($23,504)	($3,798)
Adjustments to reconcile consolidated net loss to net cash provided by (used for) operating activities:
Depreciation and amortization	9,805	10,008	10,423
Stock-based compensation expense	1,634	2,450	1,244
Provision for doubtful accounts	66
Deferred income taxes	18	4,491	-369
Impairment of goodwill			2,012
Decrease in long-term deferred revenue	-139	-139	-139
(Decrease) increase in long-term income taxes payable	-472	-155	135
Excess tax benefit of share-based compensation			-105
Gain on disposal of equipment	-22	-26	-33
Credit (gain) loss on available for sale securities	-311	78	9
Change in current assets and liabilities, net	5,682	2,107	7,859
Net cash provided by (used for) operating activities	2,191	-4,690	17,238
Investing activities:
Purchases of investments	-340		-270
Sales and maturities of investments	3,460	1,024	3,630
Additions to property, plant and equipment	-7,128	-6,179	-7,396
Proceeds from sale of equipment	22	26	33
(Increase) decrease in other assets	-43	49	-81
Net cash used for investing activities	-4,029	-5,080	-4,084
Financing activities:
Purchases of Common Stock		-17,100
Proceeds from issuance of Common Stock	788	27	9
Noncontrolling interest dividends paid	-162	-531	-378
Excess (reversal of) tax benefit of share-based compensation		-451	105
Net cash provided by (used for) financing activities	626	-18,055	-264
Effect of foreign exchange rates on cash	60	-390	-244
Net (decrease) increase in cash and cash equivalents	-1,152	-28,215	12,646
Cash and cash equivalents at beginning of period	56,339	84,554	71,908
Cash and cash equivalents at end of period	55,187	56,339	84,554
Change in assets and liabilities:
Accounts receivable	-1,151	-821	4,052
Inventories, net	3,202	33	5,591
Other current assets	1,029	-1,647	380
Accounts payable and accrued liabilities	300	4,580	-1,670
Accrued severance charges	1,855	49
Income taxes payable	26	-321	-84
Deferred revenue	421	234	-410
Change in current assets and liabilities, net	5,682	2,107	7,859
Supplemental disclosures:
Cash paid during the year for income taxes, net of refunds	($1,529)	($61)	$975

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	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]
In Thousands, unless otherwise specified
Beginning Balance at Dec. 31, 2011	$184,710	$387	$166,227	$136,362	($322)	($121,827)	$180,945	$3,765	$118
Sales of Common Stock	12	3	9				12
Noncontrolling interest dividends paid	-378							-378
Excess tax benefit of stock-based compensation	105		105				105
Stock-based compensation expense	1,244		1,244				1,244
Net settlement stock option exercises	-87		-87				-87
Components of comprehensive income, net of tax
Net income (loss)	-3,798			-4,077			-4,077	279
Other comprehensive income (loss)	165				210		210	-45
Total comprehensive income (loss)	-3,633						-3,867	234
Ending Balance at Dec. 31, 2012	181,973	390	167,498	132,285	-112	-121,827	178,352	3,621	118
Sales of Common Stock	27	2	25				27
Noncontrolling interest dividends paid	-531							-531
Reversal of excess tax benefit of stock-based compensation	-451		-451				-451
Stock-based compensation expense	2,450		2,450				2,450
Net settlement stock option exercises	-48		-48				-48
Purchase of treasury stock	-17,100					-17,100	-17,100
Components of comprehensive income, net of tax
Net income (loss)	-23,504			-23,640			-23,640	136
Other comprehensive income (loss)	-479				-414		-414	-65
Total comprehensive income (loss)	-23,983						-24,054	71
Ending Balance at Dec. 31, 2013	142,337	392	169,474	108,645	-526	-138,927	139,176	3,161	118
Sales of Common Stock	788	1	787				788
Noncontrolling interest dividends paid	-162							-162
Stock-based compensation expense	1,634		1,634				1,634
Other	6		6				6
Components of comprehensive income, net of tax
Net income (loss)	-14,070			-13,887			-13,887	-183
Other comprehensive income (loss)	19				55		55	-36
Total comprehensive income (loss)	-14,051						-13,832	-219
Ending Balance at Dec. 31, 2014	$130,552	$393	$171,901	$94,758	($471)	($138,927)	$127,772	$2,780	$118

Description_of_Business

Description of Business	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Description of Business	1.  DESCRIPTION OF BUSINESS
	Vicor Corporation (the “Company” or “Vicor”) designs, develops, manufactures, and markets modular power converters, power system components, and power systems. The Company also licenses certain rights to its technology in return for recurring royalties. The principal markets for the Company’s power converters and systems are large original equipment manufacturers (“OEMs”) and their contract manufacturers, and smaller, lower volume users, which are broadly distributed across several major market areas.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	2.  SIGNIFICANT ACCOUNTING POLICIES
	Principles of consolidation
	The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation. Certain of the Company’s Vicor Custom Power subsidiaries are not majority owned by the Company. These entities are consolidated by the Company as management believes that the Company has the ability to exercise control over their activities and operations.
	Use of estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingencies at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Such estimates and assumptions relate to the useful lives of fixed assets and identified intangible assets, recoverability of long-lived assets, fair value of long-term investments, allowances for doubtful accounts, the net realizable value of inventory, potential reserves relating to litigation matters, accrued liabilities, accrued taxes, deferred tax valuation allowances, assumptions pertaining to share-based payments, and other reserves. Actual results could differ from those based on these estimates and assumptions, and such differences may be material to the financial statements.
	Revenue recognition
	Product revenue is recognized in the period when persuasive evidence of an arrangement with a customer exists, the products are shipped and title has transferred to the customer, the price is fixed or determinable, and collection is considered probable.
	The Company defers revenue and the related cost of sales on shipments to two stocking distributors until the distributors resell the products to their customers. The agreements with these stocking distributors allow them to receive price adjustment credits or to return qualifying products for credit, as determined by the Company, in order to reduce the amounts of slow-moving, discontinued, or obsolete product from their inventory. These stocking distributors are also granted price adjustment credits in the event of a price decrease subsequent to the date the product was shipped and invoiced to the stocking distributor. Given the uncertainties associated with the levels of price adjustment credits to be granted to stocking distributors, the sales price to the stocking distributor is not fixed or determinable until the stocking distributor resells the products to its customers. Therefore, the Company defers revenue and the related cost of sales on shipments to stocking distributors until the stocking distributors resell the products to their customers. Accordingly, the Company’s revenue fully reflects end-customer purchases and is not impacted by stocking distributor inventory levels. Agreements with stocking distributors limit returns of qualifying product to the Company to a certain percentage of the value of the Company’s shipments to that stocking distributor during the prior quarter. In addition, stocking distributors are allowed to return unsold products if the Company terminates the relationship with the stocking distributor. Title to the inventory transferred to the stocking distributor at the time of shipment or delivery to the stocking distributor, as well as payment from the stocking distributor, are due in accordance with the Company’s standard payment terms. These payment terms are not contingent upon the stocking distributors’ sale of the products to their end-customers. Upon title transfer to stocking distributors, the Company reduces inventory for the cost of goods shipped, the margin (i.e., revenues less cost of revenues) is recorded as deferred revenue, and an account receivable is recorded. As of December 31, 2014, the Company had gross deferred revenue of approximately $1,769,000 and gross deferred cost of revenues of approximately $808,000 under agreements with stocking distributors ($1,269,000 and $516,000, respectively, as of December 31, 2013).
	The Company evaluates revenue arrangements with potential multi-element deliverables to determine if there is more than one unit of accounting. A deliverable constitutes a separate unit of accounting when it has standalone value and there are no customer-negotiated refund or return rights for the undelivered elements. The Company enters into arrangements containing multiple elements that may include a combination of non-recurring engineering services (“NRE”), prototype units, and production units. The Company has determined NRE and prototype units represent one unit of accounting and production units represent a separate unit of accounting, based on an assessment of the respective standalone value. The Company defers revenue recognition for NRE and prototype units until completion of the final milestone under the NRE arrangement, which is generally the delivery of the prototype. Recognition generally takes place within six to twelve months of the initiation of the arrangement. Revenue for the production units is recognized upon shipment, consistent with other product revenue summarized above. During 2014, 2013, and 2012, revenue recognized under multi-element arrangements accounted for less than 3% of net revenues.
	License fees are recognized as earned. The Company recognizes revenue on such arrangements only when the contract is signed, the license term has begun, all obligations have been delivered to the customer, and collection is probable.
	Foreign currency translation
	The financial statements of Vicor Japan Company, Ltd. (“VJCL”), a majority-owned subsidiary, for which the functional currency is the Japanese Yen, have been translated into U.S. Dollars using the exchange rate in effect at the balance sheet date for balance sheet amounts and the average exchange rates in effect during the year for income statement amounts. The gains and losses resulting from the changes in exchange rates from year to year have been reported in other comprehensive income.
	Transaction gains and losses resulting from the remeasurement of foreign currency denominated assets and liabilities of the Company’s foreign subsidiaries where the functional currency is the U.S. Dollar are included in other income (expense), net. Foreign currency losses included in other income (expense), net, were approximately ($196,000), ($94,000), and ($46,000) in 2014, 2013, and 2012, respectively.
	Cash and cash equivalents
	Cash and cash equivalents include funds held in disbursement (i.e., checking) and money market accounts, certificates of deposit, and debt securities with maturities of less than three months at the time of purchase. Cash and cash equivalents are valued at cost, approximating market value. The Company’s money market securities, which are classified as cash equivalents on the balance sheet, are purchased and redeemed at par value. Their estimated fair value is equal to their cost, and, due to the nature of the securities and their classification as cash equivalents, there are no unrealized gains or losses recorded at the balance sheet dates.
	Short-term and 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 guidelines of the Company’s investment policy, 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 short-term and long-term investments are classified as available-for-sale securities. Available-for-sale securities are recorded 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 Total 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, 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 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.
	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 that 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:
	Level 1		Inputs used to measure fair value are unadjusted quoted prices available in active markets for the identical assets or liabilities as of the reporting date.
	Level 2		Inputs used to measure fair value, other than quoted prices included in Level 1, are either directly or indirectly observable as of the reporting date through correlation with market data, including quoted prices for similar assets and liabilities in active markets and quoted prices in inactive markets. Level 2 also includes assets and liabilities valued using models or other pricing methodologies that do not require significant judgment since the input assumptions used in the models, such as interest rates and volatility factors, are corroborated by readily observable data from actively quoted markets for substantially the full term of the financial instrument.
	Level 3		Inputs used to measure fair value are unobservable inputs supported by little or no market activity and reflect the use of significant management judgment. These values are generally determined using pricing models for which the assumptions utilize management’s estimates of market participant assumptions.
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short maturity of these financial instruments.
	Allowance for doubtful accounts
	The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments, based on assessments of customers’ credit-risk profiles and payment histories. If the financial condition of the Company’s customers were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required. The Company does not require collateral from its customers, although there have been circumstances when the Company has required cash in advance (i.e., a partial down-payment) to facilitate orders in excess of a customer’s established credit limit. To date, such amounts have not been material.
	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, historical consumption and expected market conditions. If the Company’s estimated demand and/or market expectations 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.
	Concentrations of risk
	Financial instruments potentially subjecting the Company to significant concentrations of credit risk consist principally of cash and cash equivalents, of which a significant portion is held by one financial institution, short-term and long-term investments, and trade accounts receivable. The Company maintains cash and cash equivalents and certain other financial instruments with various large financial institutions. Generally, amounts invested with these financial institutions are in excess of federal deposit insurance limits. The Company has not experienced any losses in such accounts, and management believes the Company is not exposed to significant credit risk. The Company’s short-term and long-term investments consist of highly rated (Aaa/AA+) municipal and corporate debt securities in which a significant portion are invested in an auction rate security. As of December 31, 2014, the Company was holding a single auction rate security with a par value of $3,000,000, which is collateralized by student loans. Through December 31, 2014, auctions held for the Company’s auction rate security have failed. The funds associated with an auction rate security that has failed auction may not be accessible until a successful auction occurs, a buyer is found outside of the auction process, the security is called, or the underlying securities have matured. If the credit rating of the issuer of the auction rate security held deteriorates, the Company may be required to adjust the carrying value of the investment for an other-than-temporary decline in value through an impairment charge. The Company’s investment policy, approved by the Board of Directors, limits the amount the Company may invest in any issuer, thereby reducing credit risk concentrations.
	The Company’s products are sold worldwide to customers ranging from smaller, independent manufacturers of highly specialized electronic devices, to larger OEMs and their contract manufacturers. The applications in which these products are used are in the higher-performance, higher-power segments of the power systems market, including, in alphabetical order, aerospace and defense electronics, enterprise and high performance computing, industrial automation, telecommunications and networking infrastructure, test and measurement instrumentation, and vehicles and transportation. While, overall, the Company has a broad customer base and sells into a variety of industries, the Company’s VI Chip and Picor subsidiaries have derived a substantial portion of their revenue from a limited number of customers. This concentration of revenue is a reflection of the relatively early stage of adoption of the technologies, architectures and products offered by these subsidiaries, and their targeting of market leading innovators as initial customers. Concentrations of credit risk with respect to trade accounts receivable are limited due to the number of entities comprising the Company’s customer base. As of December 31, 2014, two customers accounted for approximately 14.9% and 11.6% of trade account receivables, respectively. As of December 31, 2013, two customers accounted for approximately 12.9% and 12.5% of trade account receivables, respectively. Credit losses have consistently been within management’s expectations.
	During 2014, one customer accounted for approximately 14.7% of net revenues. During 2013, two customers accounted for approximately 10.9% and 10.1% of net revenues, respectively. During 2012, one customer accounted for approximately 10.1% of net revenues. International sales, based on customer location, as a percentage of total net revenues, were approximately 60.5% in 2014, 59.5% in 2013, and 51.1% in 2012. During 2014, net revenues from customers in Hong Kong and China accounted for approximately 20.2% and 12.0%, respectively, of total net revenues. During 2013, net revenues from customers in Hong Kong and China accounted for approximately 16.2% and 11.3%, respectively, of total net revenues. Net revenues from customers in Hong Kong and Taiwan accounted for approximately 12.5% and 9.0%, respectively, of total net revenues in 2012.
	Components and materials used in the Company’s products are purchased from a variety of vendors. While most of the components are available from multiple sources, some key components for certain VI Chip and Picor products, in particular, are supplied by single vendors. In instances of single source items, the Company maintains levels of inventories management considers appropriate to enable meeting the delivery requirements of customers. If suppliers or subcontractors cannot provide their products or services on time or to the required specifications, the Company may not be able to meet the demand for its products and its delivery times may be negatively affected.
	Long-lived assets
	The Company reviews property, plant and equipment and finite-lived intangible assets for impairment whenever events or changes in circumstances indicate the carrying value of such assets may not be recoverable. Management determines whether the carrying value of an asset or asset group is recoverable based on comparison to the undiscounted expected future cash flows the assets are expected to generate over their remaining economic lives. If an asset value is not recoverable, the impairment loss is equal to the amount by which the carrying value of the asset exceeds its fair value, which is determined by either a quoted market price, if any, or a value determined by utilizing a discounted cash flow technique. Evaluation of impairment of long-lived assets requires estimates of future operating results that are used in the preparation of the expected future undiscounted cash flows. Actual future operating results and the remaining economic lives of our long-lived assets could differ from the estimates used in assessing the recoverability of these assets. These differences could result in impairment charges, which could be material.
	Intangible assets
	Values assigned to patents are amortized using the straight-line method over periods ranging from three to 20 years. Patents and other intangible assets are included in “Other assets” in the accompanying Consolidated Balance Sheets.
	Other investments
	The Company accounts for its investment in Great Wall Semiconductor Corporation (“GWS”) under the equity method of accounting.
	Advertising expense
	The cost of advertising is expensed as incurred. The Company incurred $1,832,000, $1,884,000, and $1,910,000 in advertising costs during 2014, 2013 and 2012, respectively.
	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 influencing 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 periodically assesses the adequacy of warranty reserves and adjusts the amounts as necessary. Warranty obligations are included in “Accrued expenses” in the accompanying Consolidated Balance Sheets.
	Legal Costs
	Legal costs in connection with litigation are expensed as incurred.
	Net loss per common share
	The Company computes basic earnings per share using the weighted average number of common shares outstanding and diluted earnings per share using the weighted average number of common shares outstanding plus the effect of outstanding dilutive stock options, if any. The following table sets forth the computation of basic and diluted loss per share for the years ended December 31 (in thousands, except per share amounts):
			2014			2013			2012
	Numerator:
	Net loss attributable to Vicor Corporation		$	(13,887	)	$	(23,640	)	$	(4,077	)
	Denominator:
	Denominator for basic loss per share-weighted average shares (1)			38,569			39,195			41,811
	Effect of dilutive securities:
	Employee stock options (2)			—			—			—
	Denominator for diluted loss per share — adjusted weighted-average shares and assumed conversions (3)			38,569			39,195			41,811
	Basic loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	Diluted loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	-1	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding.
	-2	Options to purchase 1,895,675, 1,989,248, and 545,345 shares of Common Stock in 2014, 2013, and 2012, respectively, were not included in the calculation of net loss per share as the effect would have been antidilutive.
	-3	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding for the year, adjusted to include the dilutive effect, if any, of outstanding options.
	Income taxes
	Deferred tax assets and liabilities are determined based on the differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted income tax rates and laws expected to be in effect when the temporary differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if management determines it is more likely than not that some portion or all of the deferred tax assets will not be realized. Additionally, deferred tax assets and liabilities are separated into current and noncurrent amounts based on the classification of the related assets and liabilities for financial reporting purposes (or the expected reversal thereof).
The Company follows a two-step process to determine the amount of tax benefit to recognize. The first step is to evaluate the tax position to determine the likelihood it would be sustained upon examination by a tax authority. If the tax position is deemed “more-likely-than-not” to be sustained, the second step is to assess the tax position to determine the amount of tax benefit to be recognized in the financial statements. The amount of the benefit that may be recognized is the largest amount that possesses greater than 50 percent likelihood of being realized upon ultimate settlement. If the tax position does not meet the “more-likely-than-not” threshold, then it is not recognized in the financial statements. Additionally, the Company accrues interest and penalties, if any, related to unrecognized tax benefits as a component of income tax expense. The unrecognized tax benefits, including accrued interest and penalties, if any, are included in “Long-term income taxes payable” in the accompanying Consolidated Balance Sheets.
Stock-based compensation
The Company uses the Black-Scholes option-pricing model to calculate the grant-date fair value of stock option awards, whether they possess time-based vesting provisions or performance-based vesting provisions. For stock options with time-based vesting provisions, the calculated compensation expense, net of expected forfeitures, is recognized on a straight-line basis over the service period of the award, which is generally five years for stock options. For stock options with performance-based vesting provisions, recognition of compensation expense, net of expected forfeitures, commences if and when the achievement of the performance criteria is deemed probable. For stock options with performance-based vesting provisions, compensation expense, net of expected forfeitures, when recognized, is recognized over the relevant performance period.
Comprehensive income (loss)
The components of comprehensive income (loss) include, in addition to net income (loss), unrealized gains and losses on investments, net of tax and foreign currency translation adjustments related to VJCL, net of tax.
Impact of recently issued accounting standards
In May 2014, the Financial Accounting Standards Board (“FASB”) issued new guidance for revenue recognition, which will require an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The new guidance will replace most existing revenue recognition guidance in U.S. Generally Accepted Accounting Principles when it becomes effective which, for the Company, will be on January 1, 2017. Early application is not permitted. The standard permits the use of either the retrospective or cumulative effect transition method. The Company is evaluating the effect the new guidance will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting.
Effective January 1, 2014, the Company adopted new 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. The adoption of this new guidance did not impact the Company’s financial position or results of operations.

StockBased_Compensation_and_Em

Stock-Based Compensation and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation and Employee Benefit Plans	3.   STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS
	Vicor currently grants options for the purchase of common stock (i.e., “stock options”) under the following equity compensation plans that are stockholder-approved:
	Amended and Restated 2000 Stock Option and Incentive Plan (the “2000 Plan”) — Under the 2000 Plan, the Board of Directors or the Compensation Committee of the Board of Directors may grant stock incentive awards based on the Company’s Common Stock, including stock options, stock appreciation rights, restricted stock, performance shares, unrestricted stock, deferred stock, and dividend equivalent rights. Awards may be granted to employees and other key persons, including non-employee directors. Incentive stock options may be granted to employees at a price at least equal to the fair market value per share of the Common Stock on the date of grant, and non-qualified options may be granted to non-employee directors at a price at least equal to 85% of the fair market value of the Common Stock on the date of grant. A total of 4,000,000 shares of Common Stock have been reserved for issuance under the 2000 Plan. The period of time during which an option may be exercised and the vesting periods are determined by the Compensation Committee. The term of each option may not exceed 10 years from the date of grant.
	Picor Corporation (“Picor”), a privately held, majority-owned subsidiary of Vicor, currently grants stock options under the following equity compensation plan that has been approved by its Board of Directors:
	2001 Stock Option and Incentive Plan, as amended (the “2001 Picor Plan”) — Under the 2001 Picor Plan, the Board of Directors of Picor may grant equity-based awards associated with Picor Common Stock, including stock options, restricted stock, or unrestricted stock. Awards may be granted to employees and other key persons, including non-employee directors and full or part-time officers. No incentive stock options have been granted since November 11, 2011, and no such option were outstanding as of December 31, 2014. Non-qualifying stock options may be granted to employees at a price at least equal to the fair market value per share of Picor Common Stock, based on judgments made by Picor’s Board of Directors on the date of grant. All stock option awards must be approved by both the Picor Board of Directors and the Compensation Committee of the Company’s Board of Directors. A total of 20,000,000 shares of Picor Common Stock have been reserved for issuance under the 2001 Picor Plan. The period of time during which an option may be exercised and the vesting periods are determined by the Picor Board of Directors. The term of each option may not exceed 10 years from the date of grant.
	VI Chip Corporation (“VI Chip”), a privately held, majority-owned subsidiary of Vicor, currently grants stock options under the following equity compensation plan that has been approved by its Board of Directors:
	2007 Stock Option and Incentive Plan, as amended (the “2007 VI Chip Plan”) — Under the 2007 VI Chip Plan, the Board of Directors of VI Chip may grant equity-based awards associated with VI Chip Common Stock, including stock options, restricted stock, or unrestricted stock. Awards may be granted to employees and other key persons, including non-employee directors and full or part-time officers. No incentive stock options have been granted since November 11, 2011, and no such option were outstanding as of December 31, 2014. Non-qualifying stock options may be granted to employees at a price at least equal to the fair market value per share of the VI Chip Common Stock, based on judgments made by VI Chip’s Board of Directors on the date of grant. A total of 12,000,000 shares of VI Chip Common Stock have been reserved for issuance under the 2007 VI Chip Plan. The period of time during which an option may be exercised and the vesting periods are determined by the VI Chip Board of Directors. The term of each option may not exceed 10 years from the date of grant.
	All time-based (i.e., non-performance-based) options for the purchase of Vicor common stock are granted at an exercise price equal to or greater than the market price for Vicor common stock at the date of the grant. All time-based (i.e., non-performance-based) options for the purchase of VI Chip or Picor common stock are granted at an exercise price equal to or greater than the estimated fair market value of the respective share price, based on a value calculated using a discounted cash flow model at the date of grant consistent with the requirements of Section 409A of the Internal Revenue Code.
	On May 17, 2013, the Company commenced an Offer to Exchange (the “Exchange Offer”) to its employees and directors to voluntarily exchange certain outstanding options to purchase shares of the Company’s common stock granted under the 2000 Plan, on a one-for-one basis, for replacement options to purchase shares of common stock, also 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 (the “BBU”) (“Performance-Based Eligible Options”). Options for the purchase of shares of common stock of the Company’s subsidiaries, VI Chip and Picor, 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 resulted 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 $940,000 as of December 31, 2014.
	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 58,250 of these Performance-Based Eligible Options remain outstanding as of December 31, 2014. 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 December 31, 2014, the Company determined it was not probable the revenue targets would 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 $365,000 as of December 31, 2014.
	On December 31, 2010, the Company granted 2,984,250 non-qualified stock options under the 2007 VI Chip 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 would 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 December 31, 2014 and, accordingly, expense has been recorded through that date. The unrecognized compensation expense for these performance-based options was approximately $621,000 as of December 31, 2014.
	During the fourth quarter of 2014, the Company, in effect, cancelled certain stock options previously awarded to three corporate officers in 2013 and awarded to those officers new stock options representing an equivalent value, as calculated using the Black-Scholes option-pricing model. Subsequent to the 2013 awards, the Company determined those grants exceeded the limit on the number of stock options that may be granted to an individual in a year, according to the terms of the 2000 Plan. In connection with this action, recorded for financial reporting purposes as a modification of existing options, a total of 129,028 stock options awarded in 2013 were cancelled and a total of 150,355 new stock options were awarded. The cancellation of the 2013 stock options and the award of new stock options did not have a material impact on the Company’s results of operations.
	Stock-based compensation expense for the years ended December 31 was as follows (in thousands):
			2014			2013			2012
	Cost of revenues		$	183		$	163		$	45
	Selling, general and administrative			1,176			1,942			864
	Research and development			275			345			335
	Total stock-based compensation		$	1,634		$	2,450		$	1,244
	The decrease in stock-based compensation expense in 2014 compared to 2013 and the increase in stock-based compensation expense in 2013 compared to 2012 were both primarily due to the Offer to Exchange, described above.
	The fair value for options awarded for the years shown below was estimated at the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:
			Non Performance-
			based Stock
			Options
	Vicor:		2014			2013			2012
	Risk-free interest rate			2.2	%		1.2	%		0.7	%
	Expected dividend yield			—			—			0.6	%
	Expected volatility			52	%		39	%		52	%
	Expected lives (years)			6.6			4.9			4.1
	VI Chip:		2014			2013			2012
	Risk-free interest rate			2.3	%		1.6	%		1.2	%
	Expected dividend yield			—			—			—
	Expected volatility			41	%		48	%		50	%
	Expected lives (years)			6.5			6.5			6.5
	Picor:		2014			2013			2012
	Risk-free interest rate			2.2	%		1.2	%		1.2	%
	Expected dividend yield			—			—			—
	Expected volatility			42	%		49	%		50	%
	Expected lives (years)			6.5			6.5			6.5
	Risk-free interest rate:
	Vicor — The Company uses the yield on zero-coupon U.S. Treasury “Strip” securities for a period that is commensurate with the expected term assumption for each vesting period.
	Picor and VI Chip — Picor and VI Chip use the yield to maturity of a seven-year U.S. Treasury bond, as it most closely aligns to the expected exercise period.
	Expected dividend yield:
	Vicor — The Company determines the expected dividend yield by annualizing the most recent prior cash dividends declared by the Company’s Board of Directors and dividing that result by the closing stock price on the date of that dividend declaration. Dividends are not paid on options.
	Picor and VI Chip — Picor and VI Chip have not and do not expect to declare and pay dividends in the foreseeable future. Therefore, the expected dividend yield is not applicable.
	Expected volatility:
	Vicor — Vicor uses historical volatility to estimate the grant-date fair value of the options, using the expected term for the period over which to calculate the volatility (see below). The Company does not expect its future volatility to differ from its historical volatility. The computation of the Company’s volatility is based on a simple average calculation of monthly volatilities over the expected term.
	Picor — As Picor is a nonpublic entity, historical volatility information is not available. An industry sector index of six publicly traded fabless semiconductor firms was developed for calculating historical volatility for Picor. Historical prices for each of the companies in the index based on the market price of the shares on each day of trading over the expected term were used to determine the historical volatility.
	VI Chip — As VI Chip is a nonpublic entity, historical volatility information is not available. An industry sector index of 11 publicly traded fabless semiconductor firms was developed for calculating historical volatility for VI Chip. Historical prices for each of the companies in the index based on the market price of the shares on each day of trading over the expected term were used to determine the historical volatility.
	Expected term:
	Vicor — The Company uses historical employee exercise and option expiration data to estimate the expected term assumption for the Black-Scholes grant-date valuation. The Company believes this historical data is currently the best estimate of the expected term of options, and all groups of the Company’s employees exhibit similar exercise behavior.
	Picor and VI Chip — Due to the lack of historical information, the “simplified” method as prescribed by the Securities and Exchange Commission was used to determine the expected term on grant awards that meet the definition of “plain vanilla”. For options that did not meet the criteria of “plain vanilla”, the Company calculated the expected term based on its best estimate of what the expected term would be.
	Forfeiture rate:
	The amount of stock-based compensation recognized during a period is based on the value of the portion of the awards that are ultimately expected to vest. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The term “forfeitures” is distinct from “cancellations” or “expirations” and represents only the unvested portion of the surrendered option. The forfeiture analysis is re-evaluated quarterly and the forfeiture rate is adjusted as necessary. Ultimately, the actual expense recognized over the vesting period will only be for those shares that vest.
	Vicor — The Company currently expects, for Vicor options, based on an analysis of historical forfeitures, approximately 78% of its options will actually vest. An annual forfeiture rate of 8.0% has been applied to all unvested options as of December 31, 2014. For 2013, the Company similarly expected 78% of its options would actually vest and applied an annual forfeiture rate of 8.00%.
	Picor — The Company currently expects, for Picor options, based on an analysis of historical forfeitures, approximately 92% of its options will actually vest. An annual forfeiture rate of 2.75% has been applied to all unvested options as of December 31, 2014. For 2013, the Company similarly expected 92% of its options would actually vest and applied an annual forfeiture rate of 2.75%.
	VI Chip — The Company currently expects, for VI Chip options, based on an analysis of historical forfeitures, approximately 77% of its options will actually vest. An annual forfeiture rate of 7.75% has been applied to all unvested options as of December 31, 2014. For 2013, the Company expected 80% of its options would actually vest and applied an annual forfeiture rate of 7.00%.
	Vicor Stock Options
	A summary of the activity under the 2000 Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
			Options			Weighted-			Weighted-			Aggregate
			Outstanding			Average			Average			Intrinsic
			Exercise			Remaining			Value
			Price			Contractual
						Life in
						Years
Outstanding on December 31, 2013			1,989,248		$	7.71
Granted			343,650		$	9.24
Forfeited and expired			(310,182	)	$	7.83
Exercised			(127,041	)	$	6.2
Outstanding on December 31, 2014			1,895,675		$	8.01			8.41		$	7,796
Exercisable on December 31, 2014			306,173		$	6.9			7.85		$	1,642
Vested or expected to vest as of December 31, 2014(1)			1,707,311		$	7.97			8.42		$	7,167
-1	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. The number of options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.
As of December 31, 2013 and 2012, the Company had options exercisable for 54,284 and 255,694 shares respectively, for which the weighted average exercise prices were $9.72 and $12.79, respectively.
During the years ended December 31, 2014, 2013, and 2012 under all plans, the total intrinsic value of Vicor options exercised (i.e., the difference between the market price at exercise and the price paid by the employee to exercise the options) was $751,000, $15,000, and $2,000, respectively. The total amount of cash received by the Company from options exercised in 2014, 2013, and 2012, was $788,000, $13,000, and $4,000, respectively. The total grant-date fair value of stock options that vested during the years ended December 31, 2014, 2013, and 2012 was approximately $1,096,000, $489,000, and $449,000, respectively.
As of December 31, 2014, there was $1,369,000 of total unrecognized compensation cost related to unvested non-performance based awards for Vicor. That cost is expected to be recognized over a weighted-average period of 2.16 years for those awards. The expense will be recognized as follows: $705,000 in 2015, $399,000 in 2016, $195,000 in 2017, $62,000 in 2018, and $8,000 in 2019.
The weighted-average fair value of Vicor options granted was $5.50, $1.90, and $2.47, in 2014, 2013, and 2012, respectively.
Picor Stock Options
A summary of the activity under the 2001 Picor Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
		Options			Weighted-			Weighted-			Aggregate
		Outstanding			Average			Average			Intrinsic
					Exercise			Remaining			Value
					Price			Contractual
								Life in
								Years
Outstanding on December 31, 2013			9,404,367		$	0.66
Granted			1,150,400		$	0.41
Forfeited and expired			(684,700	)	$	0.73
Exercised			—		$	—
Outstanding on December 31, 2014			9,870,067		$	0.62			5.89		$	—
Exercisable on December 31, 2014			6,643,377		$	0.67			5.08		$	—
Vested or expected to vest as of December 31, 2014(1)			9,749,482		$	0.62			5.86		$	—
-1	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.
As of December 31, 2013 and 2012, Picor had options exercisable for 5,869,044 and 5,329,950 shares, respectively, for which the weighted average exercise prices were $0.69 and $0.69, respectively.
During the years ended December 31, 2013, and 2012, the total intrinsic value of Picor options exercised was $146,000 and $279,000, respectively. There were no Picor options exercised in 2014. The total amounts of cash received by Picor from options exercised in 2013 and 2012 were $14,000 and $172,000, respectively. The total grant-date fair value of stock options vesting during the years ended December 31, 2014, 2013, and 2012 was approximately $0, $398,000, and $61,000, respectively.
As of December 31, 2014, there was $631,000 of total unrecognized compensation cost related to unvested share-based awards for Picor. That cost is expected to be recognized over a weighted-average period of 2.7 years for all Picor awards. The expense will be recognized as follows: $358,000 in 2015, $140,000 in 2016, $78,000 in 2017, $43,000 in 2018, and $12,000 in 2019.
The weighted-average fair value of Picor options granted was $0.19 in 2014, $0.31 in 2013, and $0.32 in 2012.
VI Chip Stock Options
A summary of the activity under the 2007 VI Chip Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
		Options			Weighted-			Weighted-			Aggregate
		Outstanding			Average			Average			Intrinsic
					Exercise			Remaining			Value
					Price			Contractual
								Life in
								Years
Outstanding on December 31, 2013			10,744,250		$	1
Granted			117,500		$	1
Forfeited and expired			(146,750	)	$	1.01
Exercised			—		$	—
Outstanding on December 31, 2014 (1)			10,715,000		$	1			3.83		$	—
Exercisable on December 31, 2014			7,377,950		$	1			2.64		$	—
Vested or expected to vest as of December 31, 2014(2)			10,423,793		$	1			3.75		$	—
-1	Of the total VI Chip options outstanding on December 31, 2014, 5,500,000 options had been granted to Dr. Vinciarelli, the Company’s Chief Executive Officer.
-2	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.
As of December 31, 2013 and 2012, VI Chip had options exercisable for 7,267,600 and 7,304,100 shares, respectively, for which the weighted average exercise price was $1.00.
There were no VI Chip options exercised in 2014 and 2013. The total intrinsic value of VI Chip options exercised in 2012 was negligible. The total amount of cash received by VI Chip from options exercised in 2012 was $6,000.
As of December 31, 2014, there was $820,000 of total unrecognized compensation cost related to unvested share-based awards for VI Chip. That cost is expected to be recognized over a weighted-average period of 1.4 years for all VI Chip awards. The expense will be recognized as follows: $233,000 in 2015, $192,000 in 2016, $177,000 in 2017, $149,000 in 2018, and $69,000 in 2019.
The weighted-average fair value of VI Chip options granted was $0.02, $0.29, and $0.46 in 2014, 2013, and 2012, respectively.
401(k) Plan
The Company sponsors a savings plan available to all domestic employees, which qualifies under Section 401(k) of the Internal Revenue Code. Employees may contribute to the plan in amounts representing from 1% to 80% of their pre-tax salary, subject to statutory limitations. The Company matches employee contributions to the plan at a rate of 50%, up to the first 3% of an employee’s compensation. The Company’s matching contributions currently vest at a rate of 20% per year, based upon years of service. The Company’s contributions to the plan were approximately $877,000, $825,000, and $813,000 in 2014, 2013, and 2012, respectively.
Stock Bonus Plan
Under the Company’s 1985 Stock Bonus Plan, as amended, shares of Common Stock may be awarded to employees from time to time as determined by the Board of Directors. On December 31, 2014, 109,964 shares were available for further award. All shares awarded to employees under this plan have vested. No further awards are contemplated under this plan at the present time.

ShortTerm_and_LongTerm_Investm

Short-Term and Long-Term Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Short-Term and Long-Term Investments	4.  SHORT-TERM AND LONG-TERM INVESTMENTS
	As of December 31, 2014, the Company held one auction rate security with a par value of $3,000,000. This auction rate security consists of a collateralized debt obligation, supported by a pool of student loans, sponsored by state student loan agencies and corporate student loan servicing firms. The interest rate for the security is reset at regular intervals ranging from seven to 28 days. The auction rate security held by the Company traded at par prior to February 2008 and is 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 December 31, 2014, the Company held one auction rate security that had experienced failed auctions, representing $3,000,000 at par value, (the “Failed Auction Security”), compared to December 31, 2013, when the Company had auction rate securities, including the Failed Auction Security, that had experienced failed auctions of $6,000,000 at par value, 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 Security held by the Company is Aaa/AA+ rated by the major credit rating agencies, which is collateralized by student loans, and is guaranteed by the U.S. Department of Education under the Federal Family Education Loan Program. Management is not aware of any reason to believe the issuer of the Failed Auction Security is presently at risk of default. Through December 31, 2014, the Company has continued to receive interest payments on the Failed Auction Security in accordance with the terms of its indenture. Management believes the Company ultimately should be able to liquidate the Failed Auction Security without significant loss primarily due to the overall quality of the issue held and the collateral securing the substantial majority of the underlying obligation. However, current conditions in the auction rate securities market have led management to conclude the recovery period for the Failed Auction Security exceeds 12 months. As a result, the Company continued to classify the Failed Auction Security as long-term as of December 31, 2014.
	The following is a summary of available-for-sale securities (in thousands):
	December 31, 2014	Cost			Gross			Gross		Estimated Fair
					Unrealized			Unrealized		Value
					Gains			Losses
	Failed Auction Security	$	3,000		$	—		$	425	$	2,575
	Brokered certificates of deposit		700			—			3		697
		$	3,700		$	—		$	428	$	3,272
	December 31, 2013	Cost			Gross			Gross		Estimated Fair
					Unrealized			Unrealized		Value
					Gains			Losses
	Failed Auction Securities	$	6,000		$	—		$	1,175	$	4,825
	Brokered certificates of deposit		820			6			—		826
		$	6,820		$	6		$	1,175	$	5,651
	All of the Failed Auction Securities as of December 31, 2014 and 2013, respectively have been in an unrealized loss position for greater than 12 months. A Failed Auction Security held as of December 31, 2013 was redeemed at par value of $3,000,000 during the fourth quarter of 2014.
	The amortized cost and estimated fair value of available-for-sale securities on December 31, 2014, by contractual maturities, are shown below (in thousands):
		Cost			Estimated
					Fair Value
	Due in one year or less	$	270		$	270
	Due in two to ten years		430			427
	Due in ten to twenty years		—			—
	Due in twenty to forty years		3,000			2,575
		$	3,700		$	3,272
	Based on the fair value measurements described in Note 5, the fair value of the Failed Auction Security on December 31, 2014, with a par value of $3,000,000, was estimated by the Company to be approximately $2,575,000. The gross unrealized loss of $425,000 on the Failed Auction Securities consists of two types of estimated loss: an aggregate credit loss of $84,000 and an aggregate temporary impairment of $341,000. 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 5).
	The following table represents a rollforward of the activity related to the credit loss recognized in earnings on available-for-sale auction rate securities held by the Company for the years ended December 31 (in thousands):
		2014			2013			2012
	Balance at the beginning of the period	$	395		$	317		$	308
	Reductions for securities sold during the period		(272	)		(7	)		—
	Additions for the amount related to credit loss for which other-than-temporary impairment was not previously recognized		(39	)		85			9
	Balance at the end of the period	$	84		$	395		$	317
	At this time, the Company has no intent to sell the Failed Auction Security and does not believe it is more likely than not the Company will be required to sell the security. 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 the investment through impairment charges recorded in the 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 Security held will affect the Company’s ability to execute its current operating plan.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	5.  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 December 31, 2014 (in thousands):
		Using
		Quoted Prices			Significant			Significant			Total Fair
		in Active			Other			Unobservable			Value as of
		Markets			Observable			Inputs			December 31,
		(Level 1)			Inputs			(Level 3)			2014
					(Level 2)
	Cash equivalents:
	Money market funds	$	11,207		$	—		$	—		$	11,207
	Short-term investments:
	Brokered certificates of deposit		—			270			—			270
	Long-term investments:
	Failed Auction Security		—			—			2,575			2,575
	Brokered certificates of deposit		—			427			—			427
	Assets measured at fair value on a recurring basis include the following as of December 31, 2013 (in thousands):
		Using
		Quoted Prices			Significant			Significant			Total Fair
		in Active			Other			Unobservable			Value as of
		Markets			Observable			Inputs			December 31,
		(Level 1)			Inputs			(Level 3)			2013
					(Level 2)
	Cash equivalents:
	Money market funds	$	12,407		$	—		$	—		$	12,407
	Short-term investments:
	Brokered certificates of deposit		—			463			—			463
	Long-term investments:
	Failed Auction Securities		—			—			4,825			4,825
	Brokered certificates of deposit		—			363			—			363
	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 December 31, 2014, there was insufficient observable auction rate security market information available to determine the fair value of the Failed Auction Security using Level 1 or Level 2 inputs. As such, the Company’s investment in the Failed Auction Security was deemed to require valuation using Level 3 inputs. Management, after consulting with advisors, valued the Failed Auction Security 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 this security as of December 31, 2014. 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 2.8%; the rate of return required by investors to own these securities in the current environment, which we estimate 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 Security 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 Security. 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 Security by approximately $100,000.
	For purposes of the valuation process for the Failed Auction Security, “management” consists of senior members of the Company’s finance department. The fair value measurements for the Failed Auction Security 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 Security 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 December 31, 2014 are as follows (dollars in thousands):
		Fair			Valuation		Unobservable Input	Weighted
		Value			Technique			Average
	Failed Auction Security	$	2,575		Discounted		Cumulative probability of earning		0.02	%
					cash flow		the maximum rate until maturity
							Cumulative probability of principal		93.74	%
							return prior to maturity
							Cumulative probability of default		6.24	%
							Liquidity risk premium		5	%
							Recovery rate in default		40	%
	The following table summarizes the change in the fair values for those assets valued on a recurring basis utilizing Level 3 inputs for the year ended December 31, 2014 (in thousands):
	Balance at the beginning of the period	$	4,825
	Redemptions		(3,000	)
	Credit gains on available for sales securities included in Other income (expense), net		311
	Gain included in Other comprehensive income (loss)		439
	Balance at the end of the period	$	2,575

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories	6.  INVENTORIES
	Inventories as of December 31 were as follows (in thousands):
		2014		2013
	Raw materials	$	18,252	$	19,744
	Work-in-process		3,339		3,979
	Finished goods		4,737		5,973
	Net balance	$	26,328	$	29,696

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	7.  PROPERTY, PLANT AND EQUIPMENT
	Property, plant and equipment are stated at cost and are depreciated and amortized over a period of three to 39 years generally under the straight-line method for financial reporting purposes and accelerated methods for income tax purposes.
	Property, plant and equipment as of December 31 were as follows (in thousands):
		2014			2013
	Land	$	2,089		$	2,089
	Buildings and improvements		43,800			43,083
	Machinery and equipment		228,663			224,481
	Furniture and fixtures		5,905			6,047
	Construction in-progress and deposits		2,568			1,327
			283,025			277,027
	Accumulated depreciation and amortization		(245,638	)		(236,935	)
	Net balance	$	37,387		$	40,092
	Depreciation expense for the years ended December 31, 2014, 2013 and 2012 was approximately $9,833,000, $10,180,000, and $10,546,000 respectively. As of December 31, 2014, the Company had approximately $841,000 of capital expenditure commitments.

Other_Investments

Other Investments	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Other Investments	8.  OTHER INVESTMENTS
	The Company’s gross investment in non-voting convertible preferred stock of GWS totaled $5,000,000 as of December 31, 2014, and December 31, 2013, 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 $2,146,000, $1,959,000, and $2,087,000 in 2014, 2013, and 2012, respectively. The Company owed GWS approximately $170,000 and $152,000 as of December 31, 2014 and 2013, 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.
	The balance in the Company’s net investment in GWS was zero as of December 31, 2014 and 2013.

Intangible_Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	9.  INTANGIBLE ASSETS
	Patent costs, which are included in other assets in the accompanying balance sheets, as of December 31 were as follows (in thousands):
		2014			2013
	Patent costs	$	2,721		$	3,170
	Accumulated amortization		(1,689	)		(2,007	)
		$	1,032		$	1,163
	Definite lived intangible assets, such as patent rights, are amortized and tested for impairment if a triggering event occurs.
	Patent renewal fees were $25,000 and $38,000 in 2014 and 2013, respectively.
	Amortization expense was approximately $170,000, $264,000 and $314,000 in 2014, 2013 and 2012, respectively. The estimated future amortization expense from patent assets held as of December 31, 2014, is projected to be $143,000, $130,000, $124,000, $108,000 and $102,000, in fiscal years 2015, 2016, 2017, 2018, and 2019, respectively.
	In 2012, the Company performed the first step of the quantitative goodwill impairment assessment for VJCL and determined the carrying value of VJCL exceeded its fair value. The Company, therefore, performed the second step of its evaluation to calculate the impairment and, as a result, recorded a full impairment charge of $2,012,000 during the fourth quarter of 2012.

Severance_and_Other_Charges

Severance and Other Charges	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Severance and Other Charges	10.  SEVERANCE AND OTHER CHARGES
	In July 2014, the Company’s management authorized the consolidation of the manufacturing of Westcor division products, of the Brick Business Unit segment, by transferring those operations from Westcor’s Sunnyvale, California facility to the Company’s primary manufacturing facility in Andover, Massachusetts, by the end of 2014. As a result, the Company recorded a pre-tax charge of $2,207,000 in the second half of 2014, primarily for the cost of severance and other employee-related costs involving cash payments based on each employee’s respective length of service. The Company also incurred other costs related to the relocation of the manufacturing operations, primarily freight costs for the transfer of inventories and equipment, and employee travel expenses, of which approximately $303,000 was expensed in the second half of 2014. The severance payments will commence in January 2015. These charges were recorded as “Severance and other charges” in the Consolidated Statement of Operations. The related liability is presented as “Accrued severance charges” in the Consolidated Balance Sheets.
	A summary of the activity related to the severance charges, is as follows (in thousands):
	Balance as of December 31, 2013	$	—
	Charges		1,904
	Payments		—
	Balance as of December 31, 2014	$	1,904

Product_Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Product Warranties	11.  PRODUCT	WARRANTIES
	Product warranty activity for the years ended December 31 was as follows (in thousands):
			2014			2013			2012
	Balance at the beginning of the period		$	283		$	364		$	572
	Accruals for warranties for products sold in the period			281			327			439
	Fulfillment of warranty obligations			(350	)		(297	)		(554	)
	Revisions of estimated obligations			(10	)		(111	)		(93	)
	Balance at the end of the period		$	204		$	283		$	364

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	12.  STOCKHOLDERS’ EQUITY
	Each share of Common Stock entitles the holder thereof to one vote on all matters submitted to the stockholders.
	Each share of Class B Common Stock entitles the holder thereof to ten votes on all such matters.
	Shares of Class B Common Stock are not transferable by a stockholder except to or among the stockholder’s spouse, certain of the stockholder’s relatives, and certain other defined transferees. Class B Common Stock is not listed or traded on any exchange or in any market. Class B Common Stock is convertible at the option of the holder thereof at any time and without cost to the stockholder into shares of Common Stock on a one-for-one basis.
	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.
	In November 2000, the Board of Directors of the Company authorized the repurchase of up to $30,000,000 of the Company’s Common Stock (the “November 2000 Plan”). The plan authorizes the Company to make repurchases from time to time in the open market or through privately negotiated transactions. The timing of this program and the amount of the stock that may be repurchased is at the discretion of management based on its view of economic and financial market conditions. There were no repurchases under the November 2000 Plan in 2014, 2013, and 2012. On December 31, 2014 and 2013, the Company had approximately $8,541,000 available for share repurchases under the November 2000 Plan.
	Dividends are declared at the discretion of the Company’s Board of Directors and depend on actual cash from operations, the Company’s financial condition and capital requirements and any other factors the Company’s Board of Directors may consider relevant at the time. Common Stock and Class B Common Stock participate in dividends and earnings equally.
	During the year ended December 31, 2014, two subsidiaries paid a total of $3,900,000 in cash dividends, of which $3,738,000 was paid to the Company and $162,000 was paid to outside shareholders. During the year ended December 31, 2013, three subsidiaries paid a total of $2,100,000 in cash dividends, of which $1,569,000 was paid to the Company and $531,000 was paid to outside shareholders. During the year ended December 31, 2012, three subsidiaries paid a total of $1,600,000 in cash dividends, of which $1,222,000 was paid to the Company and $378,000 was paid to outside shareholders. Dividends paid to outside shareholders of our subsidiaries are accounted for as a reduction in noncontrolling interest.
	During 2014, a total of 127,041 shares of Common Stock were issued upon the exercise of stock options.
	On December 31, 2014, there were 14,719,889 shares of Vicor Common Stock reserved for issuance for Vicor stock options and upon conversion of Class B Common Stock.

Other_Income_Expense_Net

Other Income (Expense), Net	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Other Income (Expense), Net	13.  OTHER INCOME (EXPENSE), NET
	The major changes in the components of other income (expense), net for the years ended December 31 were as follows (in thousands):
		2014			2013			2012
	Interest income	$	80		$	97		$	136
	Foreign currency losses, net		(196	)		(94	)		(46	)
	Gain on disposal of equipment		22			26			33
	Credit gains (losses) on available for sale securities		311			(78	)		(9	)
	Other		51			51			80
		$	268		$	2		$	194

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	14.  INCOME TAXES
	The tax provision is based on the annual effective tax rate for the year, which includes estimated federal, state and foreign income taxes on the Company’s pre-tax income 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 tax provisions also include discrete items, principally related to tax credits, tax provision vs. tax return differences and accrued interest for potential liabilities.
	The reconciliation of the federal statutory rate to the effective income tax rate for the years ended December 31 is as follows:
		2014			2013			2012
	Statutory federal tax rate		(34.0	%)		(34.0	%)		(34.0	%)
	State income taxes, net of federal income tax benefit		0.8			1.1			(9.4	)
	Tax credits		(12.4	)		(8.1	)		0.6
	U.S. manufacturing deduction		—			1.7			(3.8	)
	Permanent items		0.4			0.6			2.2
	Book income attributable to noncontrolling interest		(0.6	)		0.4			6.8
	Foreign rate differential and deferred items		(0.3	)		(0.2	)		0.1
	Increase (decrease) in tax reserves		(3.7	)		(0.1	)		0.3
	Increase in valuation allowance		46.9			53.3			84.5
	Other		—			0.1			(0.7	)
			(2.9	%)		14.8	%		46.6	%
	In 2014, the Company could not recognize a tax benefit for the majority of its losses due to a full valuation allowance against all domestic deferred tax assets, as described below. During the third quarter of 2014, the Company recognized a tax benefit of approximately $552,000 as a discrete item for the release of certain income tax reserves, due to the completion of an Internal Revenue Service examination of its 2010 and 2011 federal corporate income tax returns during the quarter (see below).
	On January 2, 2013 the American Taxpayer Relief Act of 2012 (“ATRA”) was signed into law. Under prior law, a taxpayer was entitled to a research tax credit for qualifying amounts paid or incurred on or before December 31, 2011. The ATRA, in effect, renewed the research credit for two years to December 31, 2013. The extension of the research tax credit was retroactive and includes amounts paid or incurred after December 31, 2011. Since the law was enacted in 2013, the federal research tax credit for 2012 of $549,000 was recorded as a discrete item in the first quarter of 2013.
	For financial reporting purposes, income (loss) before income taxes for the years ended December 31 include the following components (in thousands):
		2014			2013			2012
	Domestic	$	(14,223	)	$	(20,466	)	$	(3,109	)
	Foreign		(272	)		1			518
		$	(14,495	)	$	(20,465	)	$	(2,591	)
	Significant components of the provision (benefit) for income taxes for the years ended December 31 are as follows (in thousands):
		2014			2013			2012
	Current:
	Federal	$	(690	)	$	(1,848	)	$	920
	State		147			284			425
	Foreign		124			112			231
			(419	)		(1,452	)		1,576
	Deferred:
	Federal		(6	)		4,491			(369	)
		$	(425	)	$	3,039		$	1,207
	The Company intends to continue to reinvest certain of its foreign earnings indefinitely. Accordingly, no U.S. income taxes have been provided for approximately $2,940,000 of unremitted earnings of international subsidiaries. As of December 31, 2014, the amount of unrecognized deferred tax liability on these earnings was $185,000.
	Significant components of the Company’s deferred tax assets and liabilities as of December 31 were as follows (in thousands):
		2014			2013
	Deferred tax assets:
	Research and development tax credit carryforwards	$	10,756		$	8,754
	Net operating loss carryforwards		3,560			2,497
	Stock-based compensation		3,465			3,048
	Inventory reserves		3,024			2,687
	Vacation accrual		1,821			1,645
	Investment tax credit carryforwards		1,446			1,367
	Foreign tax credits		1,405			—
	Accrued severance		525			—
	Alternative minimum tax credit carryforward		340			340
	Deferred revenue		178			279
	Unrealized loss on investments		131			399
	Warranty reserves		65			88
	Bad debt reserves		59			65
	Capital loss carryforward		—			680
	Other		446			428
	Total deferred tax assets		27,221			22,277
	Less: Valuation allowance for deferred tax assets		(25,818	)		(20,214	)
	Net deferred tax assets		1,403			2,063
	Deferred tax liabilities:
	Depreciation		(176	)		(918	)
	Prepaid expenses		(755	)		(598	)
	Patent amortization		(365	)		(416	)
	Unremitted Vicor Custom Power earnings		(329	)		(335	)
	Total deferred tax liabilities		(1,625	)		(2,267	)
	Net deferred tax liabilities	$	(222	)	$	(204	)
	As of December 31, 2014, the Company has a valuation allowance of approximately $25,818,000 primarily against all domestic net deferred tax assets, for which realization cannot be considered more likely than not at this time. 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 past financial performance. In 2013, the Company recorded an increase to the valuation allowance of approximately $10,241,000 for all remaining domestic net deferred tax assets not previously covered by a valuation allowance due to the following factors: (1) the Company’s forecast of future taxable income, of the appropriate nature, based on its quarterly assessment was not sufficient to support the recoverability of the remaining domestic deferred tax assets; (2) recent cumulative losses and the Company’s projection of continued losses into 2014; (3) while the Company has the ability to carryback federal net operating losses or credits to utilize against federal taxable income, it will generate only $1,600,000 in cash refunds (which were received in the fourth quarter of 2014); and (4) the lack of prudent and feasible tax planning strategies. These assessment factors remain essentially unchanged, as the Company remains in a significant cumulative loss position as of December 31, 2014. As a result, management believes a full valuation allowance against all domestic net deferred tax assets is warranted as of December 31, 2014. The valuation allowance against these deferred tax assets may require adjustment in the future based on changes in the mix of temporary differences, changes in tax laws, and operating performance. If and when the Company determines the valuation allowance should be released (i.e., reduced), the adjustment would result in a tax benefit reported in that period’s Consolidated Statements of Operations, the effect of which would be an increase in reported net income. A portion of such an adjustment may be accounted for through an increase to “Additional paid-in capital”, a component of Stockholders’ Equity. The amount of any such tax benefit associated with release of our valuation allowance in a particular quarter may be material.
	As a result of certain realization requirements under the stock-based compensation guidance, the table of deferred tax assets and liabilities shown above does not include certain deferred tax assets as of December 31, 2014, that arose directly from tax deductions related to stock-based compensation greater than stock-based compensation recognized for financial reporting. Equity will be increased by $3,024,000 if and when such deferred tax assets are ultimately realized. The Company uses ASC 740 ordering when determining when excess tax benefits have been realized.
	The research and development tax credit carryforwards expire beginning in 2015 for state purposes and in 2025 for federal purposes. The Company has federal net operating loss carryforwards which expire beginning in 2033, as well as net operating loss carryforwards in certain states, which expire beginning in 2015 through 2034.
A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):
	2014			2013			2012
Balance on January 1	$	2,072		$	1,506		$	1,405
Additions based on tax provisions related to the current year		161			566			134
Reductions for tax positions of prior years		(967	)		—			(33	)
Lapse of statute		(12	)		—			—
Balance on December 31	$	1,254		$	2,072		$	1,506
The Company has reviewed the tax positions taken, or to be taken, in its tax returns for all tax years currently open to examination by a taxing authority. The total amount of unrecognized tax benefits, that is the aggregate tax effect of differences between tax return positions and the benefits recognized in the Company’s financial statements, as of December 31, 2014, 2013, and 2012 of $1,254,000, $2,072,000, and $1,506,000, respectively, if recognized, may decrease the Company’s income tax provision and effective tax rate. None of the unrecognized tax benefits as of December 31, 2014, are expected to significantly change during the next twelve months.
The Company recognizes accrued interest and penalties, if any, related to unrecognized tax benefits as a component of income tax expense. During the years ended December 31, 2014, 2013, and 2012, the Company recognized approximately $32,000, ($28,000), and $32,000, respectively, in net interest (benefit) expense. As of December 31, 2014 and 2013, the Company had accrued approximately $181,000 and $149,000, respectively, for the potential payment of interest.
The Company files income tax returns in the United States and various foreign tax jurisdictions. These tax returns are generally open to examination by the relevant tax authorities from three to seven years from the date they are filed. The tax filings relating to the Company’s federal and state taxes are currently open to examination for tax years 2012 and 2013 and 2007 through 2013, respectively. In addition, the 2003, 2004, and 2007 tax years resulted in losses. These years may also be subject to examination since the losses were carried forward and utilized in future years. 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 examination. The examination was completed resulting in a net refund due the Company of approximately $17,000, which was received and recorded as a discrete benefit in the third quarter of 2014.
The Company’s subsidiary in Italy, Vicor Italy S.r.l. (“Vicor Italy”), underwent during 2014 a tax inspection for tax years 2009 through 2013, covering corporation, regional and value added taxes. Vicor Italy received a preliminary tax audit report dated June 30, 2014. The Company filed a response to the preliminary tax audit report in the third quarter of 2014. While management believes it is too early to determine the likelihood or amount of potential liability at this time, it does not believe the ultimate impact of this matter will be material to the Company’s financial statements.
Other than the Vicor Italy matter discussed above there are no other income tax examinations or audits currently in process.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	15.  COMMITMENTS AND CONTINGENCIES
	The Company leases certain of its office and manufacturing space. The future minimum rental commitments under non-cancelable operating leases with remaining terms in excess of one year are as follows (in thousands):
	Year
	2015	$	1,514
	2016		811
	2017		412
	2018		139
	2019 and thereafter		120
	Rent expense was approximately $1,824,000, $1,820,000 and $1,677,000 in 2014, 2013 and 2012, respectively. The Company also pays tenant-related executory costs such as taxes, maintenance, and insurance.
	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 that date, SynQor also announced it and Ericsson had entered into a definitive settlement agreement. 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 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. On January 2, 2014, the court issued its claim construction order following a claim construction hearing held on December 17, 2013. On January 16, 2014, the Company filed a motion seeking reconsideration of certain aspects of the court’s claim construction ruling. On March 31, 2014, the court issued an order severing the case against the Company and Cisco into two separate matters, with separate trials to be held with respect to SynQor’s claims against Cisco and SynQor’s claims against the Company. On June 30, 2014, the Company filed a number of motions seeking summary judgment in this matter, including for a finding of no direct, indirect, or willful infringement and for a finding of indefiniteness with respect to U.S. Patent No. 7,272,021. The court has yet to rule on these motions. On October 23, 2014, the court issued an order continuing trial in this matter indefinitely. On January 7, 2015, the Company’s case and that of Cisco were assigned to a new judge within the U.S. District Court for the Eastern District of Texas. On January 30, 2015, SynQor filed a motion requesting a status conference. That motion has not yet been addressed by the court. On February 6, 2015, SynQor filed a motion to consolidate the Company’s and Cisco’s cases for trial. That motion has not yet been briefed by the parties. As of March 6, 2015, the Company has received no notice from the court regarding the timing of rulings on our summary judgment motions or the scheduling of a trial in this matter.
	The Company continues to believe that none 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. The Company does not believe a loss is probable for this matter. If a loss were to be incurred, though, the Company cannot estimate the amount of possible loss or range of possible loss at this time.
	On February 22, 2007, the Company announced it had reached an agreement in principle with Ericsson, Inc., the U.S. affiliate of LM Ericsson, to settle a lawsuit brought by Ericsson against the Company in California state court. Under the terms of the settlement agreement entered into on March 29, 2007, after a court ordered mediation, the Company paid $50,000,000 to Ericsson, of which $12,800,000 was reimbursed by the Company’s insurance carriers. Accordingly, the Company recorded a net loss of $37,200,000 from the litigation–related settlements in the fourth quarter of 2006. The Company subsequently sought further reimbursement from its insurance carriers. On November 14, 2008, a jury in the United States District Court for the District of Massachusetts found in favor of the Company in a lawsuit against certain of its insurance carriers with respect to the Ericsson settlement. The jury awarded $17,300,000 in damages to the Company, although the verdict was subject to challenge in the trial court and on appeal. Both parties filed certain motions subsequent to the ruling and, on March 2, 2009, the judge in the case rendered his decision on the subsequent motions, reducing the jury award by $4,000,000. On March 26, 2009, the U.S. District Court, District of Massachusetts (the “Court”) issued its judgment in the matter, affirming the award of $13,300,000, plus prejudgment interest from the date of breach on March 29, 2007, through March 26, 2009, the date of judgment in the amount of approximately $3,179,000. The insurance carriers filed their appeal to this total judgment in the amount of approximately $16,479,000 and an oral argument was held in early February 2010 on the insurer’s appeal. On March 16, 2012, the U.S. Court of Appeals for the First Circuit vacated the judgment in favor of the Company and remanded the case for proceedings consistent with the Court’s opinions. On October 3, 2012, a stipulation of dismissal with prejudice was filed with the Court, reflecting the contemporaneous settlement agreement between the Company and the insurance carriers in which the Company received a cash payment of $1,975,000 in exchange for its release of the insurance carriers from future claims. The settlement amount of $1,975,000 was recorded as a gain from litigation–related settlement in the fourth quarter of 2012.
	In addition to the SynQor matter, 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	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	16.  SEGMENT	INFORMATION
	The Company has organized its business segments according to its key product lines. The BBU segment designs, develops, manufactures, and markets the Company’s modular power converters and configurable products, and also includes the six entities comprising Vicor Custom Power, the BBU operations of VJCL, and the operations of the Company’s Westcor division. 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 Vicor’s products or to third parties for separate applications.
	The Company’s Chief Executive Officer (i.e., the 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 Consolidated Financial Statements.
	The following table provides significant segment financial data as of and for the years ended December 31 (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations			Total
														-1
	2014:00:00
	Net revenues		$	184,224	$	34,701		$	15,570		$	—		$	(8,764	)	$	225,731
	Income (loss) from operations			15,499		(29,015	)		(407	)		(840	)		—			(14,763	)
	Total assets			151,923		17,677			5,691			75,758			(95,507	)		155,542
	Depreciation and amortization			4,711		3,265			410			1,419			—			9,805
	2013:00:00
	Net revenues		$	163,013	$	35,333		$	10,416		$	—		$	(9,602	)	$	199,160
	Income (loss) from operations			12,062		(28,204	)		(3,326	)		(999	)		—			(20,467	)
	Total assets			126,585		21,370			4,308			81,364			(67,987	)		165,640
	Depreciation and amortization			6,185		3,232			407			184			—			10,008
	2012:00:00
	Net revenues		$	179,919	$	38,083		$	9,724		$	—		$	(9,219	)	$	218,507
	Income (loss) from operations			28,114		(27,409	)		(2,786	)		(704	)		—			(2,785	)
	Total assets			97,507		21,105			5,365			119,007			(40,403	)		202,581
	Depreciation and amortization			4,958		3,568			414			1,483			—			10,423
	-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.

Quarterly_Results_of_Operation

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	17.  QUARTERLY RESULTS OF OPERATIONS (Unaudited)
	The following table sets forth certain unaudited quarterly financial data for the years ended December 31 (in thousands, except per share amounts):
		First			Second			Third			Fourth			Total
	2014:00:00
	Net revenues	$	53,233		$	53,361		$	58,402		$	60,735		$	225,731
	Gross margin		22,792			22,662			25,550			26,116			97,120
	Consolidated net loss		(5,426	)		(4,932	)		(3,669	)		(43	)		(14,070	)
	Net income (loss) attributable to noncontrolling interest		(48	)		(97	)		5			(43	)		(183	)
	Net loss attributable to Vicor Corporation		(5,378	)		(4,835	)		(3,674	)		—			(13,887	)
	Net loss per share attributable to Vicor Corporation:
	Basic and diluted		(0.14	)		(0.13	)		(0.10	)		—			(0.36	)
		First			Second			Third			Fourth			Total
	2013:00:00
	Net revenues	$	41,946		$	46,865		$	55,091		$	55,258		$	199,160
	Gross margin		16,607			18,461			22,980			23,431			81,479
	Consolidated net loss		(4,986	)		(4,600	)		(898	)		(13,020	)		(23,504	)
	Net income attributable to noncontrolling interest		4			16			34			82			136
	Net loss attributable to Vicor Corporation		(4,990	)		(4,616	)		(932	)		(13,102	)		(23,640	)
	Net loss per share attributable to Vicor Corporation:
	Basic and diluted		(0.12	)		(0.12	)		(0.02	)		(0.34	)		(0.60	)
	In the fourth quarter of 2013, the Company recorded an increase of $10,132,000 to the income tax valuation allowance against deferred tax assets (See Note 14).

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	VICOR CORPORATION
	SCHEDULE II
	VALUATION AND QUALIFYING ACCOUNTS
	Years ended December 31, 2014, 2013 and 2012
	Description		Balance at		Charge		Other Charges,			Balance at
			Beginning of Period		to Costs and		Deductions (1)			End of Period
					Expenses
	Allowance for doubtful accounts:
	Year ended:
	December 31, 2014		$	198,000	$	66,000	$	(81,000	)	$	183,000
	December 31, 2013			292,000		255,000		(349,000	)		198,000
	December 31, 2012			266,000		37,000		(11,000	)		292,000
	-1	Reflects uncollectible accounts written off, net of recoveries.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of consolidation	Principles of consolidation
	The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation. Certain of the Company’s Vicor Custom Power subsidiaries are not majority owned by the Company. These entities are consolidated by the Company as management believes that the Company has the ability to exercise control over their activities and operations.
Use of estimates	Use of estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingencies at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Such estimates and assumptions relate to the useful lives of fixed assets and identified intangible assets, recoverability of long-lived assets, fair value of long-term investments, allowances for doubtful accounts, the net realizable value of inventory, potential reserves relating to litigation matters, accrued liabilities, accrued taxes, deferred tax valuation allowances, assumptions pertaining to share-based payments, and other reserves. Actual results could differ from those based on these estimates and assumptions, and such differences may be material to the financial statements.
Revenue recognition	Revenue recognition
	Product revenue is recognized in the period when persuasive evidence of an arrangement with a customer exists, the products are shipped and title has transferred to the customer, the price is fixed or determinable, and collection is considered probable.
	The Company defers revenue and the related cost of sales on shipments to two stocking distributors until the distributors resell the products to their customers. The agreements with these stocking distributors allow them to receive price adjustment credits or to return qualifying products for credit, as determined by the Company, in order to reduce the amounts of slow-moving, discontinued, or obsolete product from their inventory. These stocking distributors are also granted price adjustment credits in the event of a price decrease subsequent to the date the product was shipped and invoiced to the stocking distributor. Given the uncertainties associated with the levels of price adjustment credits to be granted to stocking distributors, the sales price to the stocking distributor is not fixed or determinable until the stocking distributor resells the products to its customers. Therefore, the Company defers revenue and the related cost of sales on shipments to stocking distributors until the stocking distributors resell the products to their customers. Accordingly, the Company’s revenue fully reflects end-customer purchases and is not impacted by stocking distributor inventory levels. Agreements with stocking distributors limit returns of qualifying product to the Company to a certain percentage of the value of the Company’s shipments to that stocking distributor during the prior quarter. In addition, stocking distributors are allowed to return unsold products if the Company terminates the relationship with the stocking distributor. Title to the inventory transferred to the stocking distributor at the time of shipment or delivery to the stocking distributor, as well as payment from the stocking distributor, are due in accordance with the Company’s standard payment terms. These payment terms are not contingent upon the stocking distributors’ sale of the products to their end-customers. Upon title transfer to stocking distributors, the Company reduces inventory for the cost of goods shipped, the margin (i.e., revenues less cost of revenues) is recorded as deferred revenue, and an account receivable is recorded. As of December 31, 2014, the Company had gross deferred revenue of approximately $1,769,000 and gross deferred cost of revenues of approximately $808,000 under agreements with stocking distributors ($1,269,000 and $516,000, respectively, as of December 31, 2013).
	The Company evaluates revenue arrangements with potential multi-element deliverables to determine if there is more than one unit of accounting. A deliverable constitutes a separate unit of accounting when it has standalone value and there are no customer-negotiated refund or return rights for the undelivered elements. The Company enters into arrangements containing multiple elements that may include a combination of non-recurring engineering services (“NRE”), prototype units, and production units. The Company has determined NRE and prototype units represent one unit of accounting and production units represent a separate unit of accounting, based on an assessment of the respective standalone value. The Company defers revenue recognition for NRE and prototype units until completion of the final milestone under the NRE arrangement, which is generally the delivery of the prototype. Recognition generally takes place within six to twelve months of the initiation of the arrangement. Revenue for the production units is recognized upon shipment, consistent with other product revenue summarized above. During 2014, 2013, and 2012, revenue recognized under multi-element arrangements accounted for less than 3% of net revenues.
	License fees are recognized as earned. The Company recognizes revenue on such arrangements only when the contract is signed, the license term has begun, all obligations have been delivered to the customer, and collection is probable.
Foreign currency translation	Foreign currency translation
	The financial statements of Vicor Japan Company, Ltd. (“VJCL”), a majority-owned subsidiary, for which the functional currency is the Japanese Yen, have been translated into U.S. Dollars using the exchange rate in effect at the balance sheet date for balance sheet amounts and the average exchange rates in effect during the year for income statement amounts. The gains and losses resulting from the changes in exchange rates from year to year have been reported in other comprehensive income.
	Transaction gains and losses resulting from the remeasurement of foreign currency denominated assets and liabilities of the Company’s foreign subsidiaries where the functional currency is the U.S. Dollar are included in other income (expense), net. Foreign currency losses included in other income (expense), net, were approximately ($196,000), ($94,000), and ($46,000) in 2014, 2013, and 2012, respectively.
Cash and cash equivalents	Cash and cash equivalents
	Cash and cash equivalents include funds held in disbursement (i.e., checking) and money market accounts, certificates of deposit, and debt securities with maturities of less than three months at the time of purchase. Cash and cash equivalents are valued at cost, approximating market value. The Company’s money market securities, which are classified as cash equivalents on the balance sheet, are purchased and redeemed at par value. Their estimated fair value is equal to their cost, and, due to the nature of the securities and their classification as cash equivalents, there are no unrealized gains or losses recorded at the balance sheet dates.
Short-term and long-term investments	Short-term and 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 guidelines of the Company’s investment policy, 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 short-term and long-term investments are classified as available-for-sale securities. Available-for-sale securities are recorded 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 Total 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, 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 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.
Fair value measurements	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 that 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:
	Level 1		Inputs used to measure fair value are unadjusted quoted prices available in active markets for the identical assets or liabilities as of the reporting date.
	Level 2		Inputs used to measure fair value, other than quoted prices included in Level 1, are either directly or indirectly observable as of the reporting date through correlation with market data, including quoted prices for similar assets and liabilities in active markets and quoted prices in inactive markets. Level 2 also includes assets and liabilities valued using models or other pricing methodologies that do not require significant judgment since the input assumptions used in the models, such as interest rates and volatility factors, are corroborated by readily observable data from actively quoted markets for substantially the full term of the financial instrument.
	Level 3		Inputs used to measure fair value are unobservable inputs supported by little or no market activity and reflect the use of significant management judgment. These values are generally determined using pricing models for which the assumptions utilize management’s estimates of market participant assumptions.
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short maturity of these financial instruments.
Allowance for doubtful accounts	Allowance for doubtful accounts
	The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments, based on assessments of customers’ credit-risk profiles and payment histories. If the financial condition of the Company’s customers were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required. The Company does not require collateral from its customers, although there have been circumstances when the Company has required cash in advance (i.e., a partial down-payment) to facilitate orders in excess of a customer’s established credit limit. To date, such amounts have not been material.
Inventories	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, historical consumption and expected market conditions. If the Company’s estimated demand and/or market expectations 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.
Concentrations of risk	Concentrations of risk
	Financial instruments potentially subjecting the Company to significant concentrations of credit risk consist principally of cash and cash equivalents, of which a significant portion is held by one financial institution, short-term and long-term investments, and trade accounts receivable. The Company maintains cash and cash equivalents and certain other financial instruments with various large financial institutions. Generally, amounts invested with these financial institutions are in excess of federal deposit insurance limits. The Company has not experienced any losses in such accounts, and management believes the Company is not exposed to significant credit risk. The Company’s short-term and long-term investments consist of highly rated (Aaa/AA+) municipal and corporate debt securities in which a significant portion are invested in an auction rate security. As of December 31, 2014, the Company was holding a single auction rate security with a par value of $3,000,000, which is collateralized by student loans. Through December 31, 2014, auctions held for the Company’s auction rate security have failed. The funds associated with an auction rate security that has failed auction may not be accessible until a successful auction occurs, a buyer is found outside of the auction process, the security is called, or the underlying securities have matured. If the credit rating of the issuer of the auction rate security held deteriorates, the Company may be required to adjust the carrying value of the investment for an other-than-temporary decline in value through an impairment charge. The Company’s investment policy, approved by the Board of Directors, limits the amount the Company may invest in any issuer, thereby reducing credit risk concentrations.
	The Company’s products are sold worldwide to customers ranging from smaller, independent manufacturers of highly specialized electronic devices, to larger OEMs and their contract manufacturers. The applications in which these products are used are in the higher-performance, higher-power segments of the power systems market, including, in alphabetical order, aerospace and defense electronics, enterprise and high performance computing, industrial automation, telecommunications and networking infrastructure, test and measurement instrumentation, and vehicles and transportation. While, overall, the Company has a broad customer base and sells into a variety of industries, the Company’s VI Chip and Picor subsidiaries have derived a substantial portion of their revenue from a limited number of customers. This concentration of revenue is a reflection of the relatively early stage of adoption of the technologies, architectures and products offered by these subsidiaries, and their targeting of market leading innovators as initial customers. Concentrations of credit risk with respect to trade accounts receivable are limited due to the number of entities comprising the Company’s customer base. As of December 31, 2014, two customers accounted for approximately 14.9% and 11.6% of trade account receivables, respectively. As of December 31, 2013, two customers accounted for approximately 12.9% and 12.5% of trade account receivables, respectively. Credit losses have consistently been within management’s expectations.
	During 2014, one customer accounted for approximately 14.7% of net revenues. During 2013, two customers accounted for approximately 10.9% and 10.1% of net revenues, respectively. During 2012, one customer accounted for approximately 10.1% of net revenues. International sales, based on customer location, as a percentage of total net revenues, were approximately 60.5% in 2014, 59.5% in 2013, and 51.1% in 2012. During 2014, net revenues from customers in Hong Kong and China accounted for approximately 20.2% and 12.0%, respectively, of total net revenues. During 2013, net revenues from customers in Hong Kong and China accounted for approximately 16.2% and 11.3%, respectively, of total net revenues. Net revenues from customers in Hong Kong and Taiwan accounted for approximately 12.5% and 9.0%, respectively, of total net revenues in 2012.
	Components and materials used in the Company’s products are purchased from a variety of vendors. While most of the components are available from multiple sources, some key components for certain VI Chip and Picor products, in particular, are supplied by single vendors. In instances of single source items, the Company maintains levels of inventories management considers appropriate to enable meeting the delivery requirements of customers. If suppliers or subcontractors cannot provide their products or services on time or to the required specifications, the Company may not be able to meet the demand for its products and its delivery times may be negatively affected.
Long-lived assets	Long-lived assets
	The Company reviews property, plant and equipment and finite-lived intangible assets for impairment whenever events or changes in circumstances indicate the carrying value of such assets may not be recoverable. Management determines whether the carrying value of an asset or asset group is recoverable based on comparison to the undiscounted expected future cash flows the assets are expected to generate over their remaining economic lives. If an asset value is not recoverable, the impairment loss is equal to the amount by which the carrying value of the asset exceeds its fair value, which is determined by either a quoted market price, if any, or a value determined by utilizing a discounted cash flow technique. Evaluation of impairment of long-lived assets requires estimates of future operating results that are used in the preparation of the expected future undiscounted cash flows. Actual future operating results and the remaining economic lives of our long-lived assets could differ from the estimates used in assessing the recoverability of these assets. These differences could result in impairment charges, which could be material.
Intangible assets	Intangible assets
	Values assigned to patents are amortized using the straight-line method over periods ranging from three to 20 years. Patents and other intangible assets are included in “Other assets” in the accompanying Consolidated Balance Sheets.
Other investments	Other investments
	The Company accounts for its investment in Great Wall Semiconductor Corporation (“GWS”) under the equity method of accounting.
Advertising expense	Advertising expense
	The cost of advertising is expensed as incurred. The Company incurred $1,832,000, $1,884,000, and $1,910,000 in advertising costs during 2014, 2013 and 2012, respectively.
Product warranties	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 influencing 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 periodically assesses the adequacy of warranty reserves and adjusts the amounts as necessary. Warranty obligations are included in “Accrued expenses” in the accompanying Consolidated Balance Sheets.
Legal Costs	Legal Costs
	Legal costs in connection with litigation are expensed as incurred.
Net loss per common share	Net loss per common share
	The Company computes basic earnings per share using the weighted average number of common shares outstanding and diluted earnings per share using the weighted average number of common shares outstanding plus the effect of outstanding dilutive stock options, if any. The following table sets forth the computation of basic and diluted loss per share for the years ended December 31 (in thousands, except per share amounts):
			2014			2013			2012
	Numerator:
	Net loss attributable to Vicor Corporation		$	(13,887	)	$	(23,640	)	$	(4,077	)
	Denominator:
	Denominator for basic loss per share-weighted average shares (1)			38,569			39,195			41,811
	Effect of dilutive securities:
	Employee stock options (2)			—			—			—
	Denominator for diluted loss per share — adjusted weighted-average shares and assumed conversions (3)			38,569			39,195			41,811
	Basic loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	Diluted loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	-1	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding.
	-2	Options to purchase 1,895,675, 1,989,248, and 545,345 shares of Common Stock in 2014, 2013, and 2012, respectively, were not included in the calculation of net loss per share as the effect would have been antidilutive.
	-3	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding for the year, adjusted to include the dilutive effect, if any, of outstanding options.
Income taxes	Income taxes
	Deferred tax assets and liabilities are determined based on the differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted income tax rates and laws expected to be in effect when the temporary differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if management determines it is more likely than not that some portion or all of the deferred tax assets will not be realized. Additionally, deferred tax assets and liabilities are separated into current and noncurrent amounts based on the classification of the related assets and liabilities for financial reporting purposes (or the expected reversal thereof).
	The Company follows a two-step process to determine the amount of tax benefit to recognize. The first step is to evaluate the tax position to determine the likelihood it would be sustained upon examination by a tax authority. If the tax position is deemed “more-likely-than-not” to be sustained, the second step is to assess the tax position to determine the amount of tax benefit to be recognized in the financial statements. The amount of the benefit that may be recognized is the largest amount that possesses greater than 50 percent likelihood of being realized upon ultimate settlement. If the tax position does not meet the “more-likely-than-not” threshold, then it is not recognized in the financial statements. Additionally, the Company accrues interest and penalties, if any, related to unrecognized tax benefits as a component of income tax expense. The unrecognized tax benefits, including accrued interest and penalties, if any, are included in “Long-term income taxes payable” in the accompanying Consolidated Balance Sheets.
Stock-based compensation	Stock-based compensation
	The Company uses the Black-Scholes option-pricing model to calculate the grant-date fair value of stock option awards, whether they possess time-based vesting provisions or performance-based vesting provisions. For stock options with time-based vesting provisions, the calculated compensation expense, net of expected forfeitures, is recognized on a straight-line basis over the service period of the award, which is generally five years for stock options. For stock options with performance-based vesting provisions, recognition of compensation expense, net of expected forfeitures, commences if and when the achievement of the performance criteria is deemed probable. For stock options with performance-based vesting provisions, compensation expense, net of expected forfeitures, when recognized, is recognized over the relevant performance period.
Comprehensive income (loss)	Comprehensive income (loss)
	The components of comprehensive income (loss) include, in addition to net income (loss), unrealized gains and losses on investments, net of tax and foreign currency translation adjustments related to VJCL, net of tax.
Impact of recently issued accounting standards	Impact of recently issued accounting standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued new guidance for revenue recognition, which will require an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The new guidance will replace most existing revenue recognition guidance in U.S. Generally Accepted Accounting Principles when it becomes effective which, for the Company, will be on January 1, 2017. Early application is not permitted. The standard permits the use of either the retrospective or cumulative effect transition method. The Company is evaluating the effect the new guidance will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting.
	Effective January 1, 2014, the Company adopted new 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. The adoption of this new guidance did not impact the Company’s financial position or results of operations.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Computation of Basic and Diluted Loss Per Share	The following table sets forth the computation of basic and diluted loss per share for the years ended December 31 (in thousands, except per share amounts):
			2014			2013			2012
	Numerator:
	Net loss attributable to Vicor Corporation		$	(13,887	)	$	(23,640	)	$	(4,077	)
	Denominator:
	Denominator for basic loss per share-weighted average shares (1)			38,569			39,195			41,811
	Effect of dilutive securities:
	Employee stock options (2)			—			—			—
	Denominator for diluted loss per share — adjusted weighted-average shares and assumed conversions (3)			38,569			39,195			41,811
	Basic loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	Diluted loss per share		$	(0.36	)	$	(0.60	)	$	(0.10	)
	-1	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding.
	-2	Options to purchase 1,895,675, 1,989,248, and 545,345 shares of Common Stock in 2014, 2013, and 2012, respectively, were not included in the calculation of net loss per share as the effect would have been antidilutive.
	-3	Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding for the year, adjusted to include the dilutive effect, if any, of outstanding options.

StockBased_Compensation_and_Em1

Stock-Based Compensation and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Stock-Based Compensation Expense	Stock-based compensation expense for the years ended December 31 was as follows (in thousands):
			2014			2013			2012
	Cost of revenues		$	183		$	163		$	45
	Selling, general and administrative			1,176			1,942			864
	Research and development			275			345			335
	Total stock based compensation		$	1,634		$	2,450		$	1,244
Weighted-Average Assumptions for Fair Value for Stock Options	The fair value for options awarded for the years shown below was estimated at the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:
			Non Performance-
			based Stock
			Options
	Vicor:		2014			2013			2012
	Risk-free interest rate			2.2	%		1.2	%		0.7	%
	Expected dividend yield			—			—			0.6	%
	Expected volatility			52	%		39	%		52	%
	Expected lives (years)			6.6			4.9			4.1
	VI Chip:		2014			2013			2012
	Risk-free interest rate			2.3	%		1.6	%		1.2	%
	Expected dividend yield			—			—			—
	Expected volatility			41	%		48	%		50	%
	Expected lives (years)			6.5			6.5			6.5
	Picor:		2014			2013			2012
	Risk-free interest rate			2.2	%		1.2	%		1.2	%
	Expected dividend yield			—			—			—
	Expected volatility			42	%		49	%		50	%
	Expected lives (years)			6.5			6.5			6.5
Vicor Plan [Member]
Stock-Based Compensation Expense	A summary of the activity under the 2000 Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
			Options			Weighted-			Weighted-			Aggregate
			Outstanding			Average			Average			Intrinsic
						Exercise			Remaining			Value
						Price			Contractual
									Life in
									Years
	Outstanding on December 31, 2013			1,989,248		$	7.71
	Granted			343,650		$	9.24
	Forfeited and expired			(310,182	)	$	7.83
	Exercised			(127,041	)	$	6.2
	Outstanding on December 31, 2014			1,895,675		$	8.01			8.41		$	7,796
	Exercisable on December 31, 2014			306,173		$	6.9			7.85		$	1,642
	Vested or expected to vest as of December 31, 2014(1)			1,707,311		$	7.97			8.42		$	7,167
	-1	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. The number of options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.
Picor Plan [Member]
Stock-Based Compensation Expense	A summary of the activity under the 2001 Picor Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
			Options			Weighted-			Weighted-			Aggregate
			Outstanding			Average			Average			Intrinsic
						Exercise			Remaining			Value
						Price			Contractual
									Life in
									Years
	Outstanding on December 31, 2013			9,404,367		$	0.66
	Granted			1,150,400		$	0.41
	Forfeited and expired			(684,700	)	$	0.73
	Exercised			—		$	—
	Outstanding on December 31, 2014			9,870,067		$	0.62			5.89		$	—
	Exercisable on December 31, 2014			6,643,377		$	0.67			5.08		$	—
	Vested or expected to vest as of December 31, 2014(1)			9,749,482		$	0.62			5.86		$	—
	-1	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.
Vi Chip Plan [Member]
Stock-Based Compensation Expense	A summary of the activity under the 2007 VI Chip Plan as of December 31, 2014 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):
			Options			Weighted-			Weighted-			Aggregate
			Outstanding			Average			Average			Intrinsic
						Exercise			Remaining			Value
						Price			Contractual
									Life in
									Years
	Outstanding on December 31, 2013			10,744,250		$	1
	Granted			117,500		$	1
	Forfeited and expired			(146,750	)	$	1.01
	Exercised			—		$	—
	Outstanding on December 31, 2014 (1)			10,715,000		$	1			3.83		$	—
	Exercisable on December 31, 2014			7,377,950		$	1			2.64		$	—
	Vested or expected to vest as of December 31, 2014(2)			10,423,793		$	1			3.75		$	—
	-1	Of the total VI Chip options outstanding on December 31, 2014, 5,500,000 options had been granted to Dr. Vinciarelli, the Company’s Chief Executive Officer.
	-2	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.

ShortTerm_and_LongTerm_Investm1

Short-Term and Long-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following is a summary of available-for-sale securities (in thousands):
	December 31, 2014	Cost			Gross			Gross		Estimated Fair
					Unrealized			Unrealized		Value
					Gains			Losses
	Failed Auction Security	$	3,000		$	—		$	425	$	2,575
	Brokered certificates of deposit		700			—			3		697
		$	3,700		$	—		$	428	$	3,272
	December 31, 2013	Cost			Gross			Gross		Estimated Fair
					Unrealized			Unrealized		Value
					Gains			Losses
	Failed Auction Securities	$	6,000		$	—		$	1,175	$	4,825
	Brokered certificates of deposit		820			6			—		826
		$	6,820		$	6		$	1,175	$	5,651
Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities	The amortized cost and estimated fair value of available-for-sale securities on December 31, 2014, by contractual maturities, are shown below (in thousands):
		Cost			Estimated
					Fair Value
	Due in one year or less	$	270		$	270
	Due in two to ten years		430			427
	Due in ten to twenty years		—			—
	Due in twenty to forty years		3,000			2,575
		$	3,700		$	3,272
Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities	The following table represents a rollforward of the activity related to the credit loss recognized in earnings on available-for-sale auction rate securities held by the Company for the years ended December 31 (in thousands):
		2014			2013			2012
	Balance at the beginning of the period	$	395		$	317		$	308
	Reductions for securities sold during the period		(272	)		(7	)		—
	Additions for the amount related to credit loss for which other-than-temporary impairment was not previously recognized		(39	)		85			9
	Balance at the end of the period	$	84		$	395		$	317

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
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 December 31, 2014 (in thousands):
		Using
		Quoted Prices			Significant			Significant			Total Fair
		in Active			Other			Unobservable			Value as of
		Markets			Observable			Inputs			December 31,
		(Level 1)			Inputs			(Level 3)			2014
					(Level 2)
	Cash equivalents:
	Money market funds	$	11,207		$	—		$	—		$	11,207
	Short-term investments:
	Brokered certificates of deposit		—			270			—			270
	Long-term investments:
	Failed Auction Security		—			—			2,575			2,575
	Brokered certificates of deposit		—			427			—			427
	Assets measured at fair value on a recurring basis include the following as of December 31, 2013 (in thousands):
		Using
		Quoted Prices			Significant			Significant			Total Fair
		in Active			Other			Unobservable			Value as of
		Markets			Observable			Inputs			December 31,
		(Level 1)			Inputs			(Level 3)			2013
					(Level 2)
	Cash equivalents:
	Money market funds	$	12,407		$	—		$	—		$	12,407
	Short-term investments:
	Brokered certificates of deposit		—			463			—			463
	Long-term investments:
	Failed Auction Securities		—			—			4,825			4,825
	Brokered certificates of deposit		—			363			—			363
Quantitative Information about Level 3 Fair Value Measurements	Quantitative information about Level 3 fair value measurements as of December 31, 2014 are as follows (dollars in thousands):
		Fair			Valuation		Unobservable Input	Weighted
		Value			Technique			Average
	Failed Auction Security	$	2,575		Discounted		Cumulative probability of earning		0.02	%
					cash flow		the maximum rate until maturity
							Cumulative probability of principal		93.74	%
							return prior to maturity
							Cumulative probability of default		6.24	%
							Liquidity risk premium		5	%
							Recovery rate in default		40	%
Change in Estimated Fair Values Calculated for Assets Valued on Recurring Basis Utilizing Level 3 Inputs	The following table summarizes the change in the fair values for those assets valued on a recurring basis utilizing Level 3 inputs for the year ended December 31, 2014 (in thousands):
	Balance at the beginning of the period	$	4,825
	Redemptions		(3,000	)
	Credit gains on available for sales securities included in Other income (expense), net		311
	Gain included in Other comprehensive income (loss)		439
	Balance at the end of the period	$	2,575

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories as of December 31 were as follows (in thousands):
		2014		2013
	Raw materials	$	18,252	$	19,744
	Work-in-process		3,339		3,979
	Finished goods		4,737		5,973
	Net balance	$	26,328	$	29,696

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment as of December 31 were as follows (in thousands):
		2014			2013
	Land	$	2,089		$	2,089
	Buildings and improvements		43,800			43,083
	Machinery and equipment		228,663			224,481
	Furniture and fixtures		5,905			6,047
	Construction in-progress and deposits		2,568			1,327
			283,025			277,027
	Accumulated depreciation and amortization		(245,638	)		(236,935	)
	Net balance	$	37,387		$	40,092

Intangible_Assets_Tables

Intangible Assets (Tables) (Patents [Member])	12 Months Ended
	Dec. 31, 2014
Patents [Member]
Schedule of Patent Cost and Other Asset	Patent costs, which are included in other assets in the accompanying balance sheets, as of December 31 were as follows (in thousands):
		2014			2013
	Patent costs	$	2,721		$	3,170
	Accumulated amortization		(1,689	)		(2,007	)
		$	1,032		$	1,163

Severance_and_Other_Charges_Ta

Severance and Other Charges (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Summary of Activity Related to Severance Charges	A summary of the activity related to the severance charges, is as follows (in thousands):
	Balance as of December 31, 2013	$	—
	Charges		1,904
	Payments		—
	Balance as of December 31, 2014	$	1,904

Product_Warranties_Tables

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Product Warranty Activity	Product warranty activity for the years ended December 31 was as follows (in thousands):
		2014			2013			2012
	Balance at the beginning of the period	$	283		$	364		$	572
	Accruals for warranties for products sold in the period		281			327			439
	Fulfillment of warranty obligations		(350	)		(297	)		(554	)
	Revisions of estimated obligations		(10	)		(111	)		(93	)
	Balance at the end of the period	$	204		$	283		$	364

Other_Income_Expense_Net_Table

Other Income (Expense), Net (Tables)	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Components of Other Income	The major changes in the components of other income (expense), net for the years ended December 31 were as follows (in thousands):
		2014			2013			2012
	Interest income	$	80		$	97		$	136
	Foreign currency losses, net		(196	)		(94	)		(46	)
	Gain on disposal of equipment		22			26			33
	Credit gains (losses) on available for sale securities		311			(78	)		(9	)
	Other		51			51			80
		$	268		$	2		$	194

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Federal Statutory Rate to Effective Income Tax Rate	The reconciliation of the federal statutory rate to the effective income tax rate for the years ended December 31 is as follows:
		2014			2013			2012
	Statutory federal tax rate		(34.0	%)		(34.0	%)		(34.0	%)
	State income taxes, net of federal income tax benefit		0.8			1.1			(9.4	)
	Tax credits		(12.4	)		(8.1	)		0.6
	U.S. manufacturing deduction		—			1.7			(3.8	)
	Permanent items		0.4			0.6			2.2
	Book income attributable to noncontrolling interest		(0.6	)		0.4			6.8
	Foreign rate differential and deferred items		(0.3	)		(0.2	)		0.1
	Increase (decrease) in tax reserves		(3.7	)		(0.1	)		0.3
	Increase in valuation allowance		46.9			53.3			84.5
	Other		—			0.1			(0.7	)
			(2.9	%)		14.8	%		46.6	%
Schedule of Domestic and Foreign Components of Income (Loss) Before Income Taxes	For financial reporting purposes, income (loss) before income taxes for the years ended December 31 include the following components (in thousands):
		2014			2013			2012
	Domestic	$	(14,223	)	$	(20,466	)	$	(3,109	)
	Foreign		(272	)		1			518
		$	(14,495	)	$	(20,465	)	$	(2,591	)
Schedule of Components of Provision (Benefit) for Income Taxes	Significant components of the provision (benefit) for income taxes for the years ended December 31 are as follows (in thousands):
		2014			2013			2012
	Current:
	Federal	$	(690	)	$	(1,848	)	$	920
	State		147			284			425
	Foreign		124			112			231
			(419	)		(1,452	)		1,576
	Deferred:
	Federal		(6	)		4,491			(369	)
		$	(425	)	$	3,039		$	1,207
Schedule of Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities as of December 31 were as follows (in thousands):
		2014			2013
	Deferred tax assets:
	Research and development tax credit carryforwards	$	10,756		$	8,754
	Net operating loss carryforwards		3,560			2,497
	Stock-based compensation		3,465			3,048
	Inventory reserves		3,024			2,687
	Vacation accrual		1,821			1,645
	Investment tax credit carryforwards		1,446			1,367
	Foreign tax credits		1,405			—
	Accrued severance		525			—
	Alternative minimum tax credit carryforward		340			340
	Deferred revenue		178			279
	Unrealized loss on investments		131			399
	Warranty reserves		65			88
	Bad debt reserves		59			65
	Capital loss carryforward		—			680
	Other		446			428
	Total deferred tax assets		27,221			22,277
	Less: Valuation allowance for deferred tax assets		(25,818	)		(20,214	)
	Net deferred tax assets		1,403			2,063
	Deferred tax liabilities:
	Depreciation		(176	)		(918	)
	Prepaid expenses		(755	)		(598	)
	Patent amortization		(365	)		(416	)
	Unremitted Vicor Custom Power earnings		(329	)		(335	)
	Total deferred tax liabilities		(1,625	)		(2,267	)
	Net deferred tax liabilities	$	(222	)	$	(204	)
Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):
		2014			2013			2012
	Balance on January 1	$	2,072		$	1,506		$	1,405
	Additions based on tax provisions related to the current year		161			566			134
	Reductions for tax positions of prior years		(967	)		—			(33	)
	Lapse of statute		(12	)		—			—
	Balance on December 31	$	1,254		$	2,072		$	1,506

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Rental Commitments under Non-Cancelable Operating Leases	The Company leases certain of its office and manufacturing space. The future minimum rental commitments under non-cancelable operating leases with remaining terms in excess of one year are as follows (in thousands):
	Year
	2015	$	1,514
	2016		811
	2017		412
	2018		139
	2019 and thereafter		120

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Significant Segment Financial Data	The following table provides significant segment financial data as of and for the years ended December 31 (in thousands):
			BBU		VI Chip			Picor			Corporate			Eliminations			Total
														-1
	2014:00:00
	Net revenues		$	184,224	$	34,701		$	15,570		$	—		$	(8,764	)	$	225,731
	Income (loss) from operations			15,499		(29,015	)		(407	)		(840	)		—			(14,763	)
	Total assets			151,923		17,677			5,691			75,758			(95,507	)		155,542
	Depreciation and amortization			4,711		3,265			410			1,419			—			9,805
	2013:00:00
	Net revenues		$	163,013	$	35,333		$	10,416		$	—		$	(9,602	)	$	199,160
	Income (loss) from operations			12,062		(28,204	)		(3,326	)		(999	)		—			(20,467	)
	Total assets			126,585		21,370			4,308			81,364			(67,987	)		165,640
	Depreciation and amortization			6,185		3,232			407			184			—			10,008
	2012:00:00
	Net revenues		$	179,919	$	38,083		$	9,724		$	—		$	(9,219	)	$	218,507
	Income (loss) from operations			28,114		(27,409	)		(2,786	)		(704	)		—			(2,785	)
	Total assets			97,507		21,105			5,365			119,007			(40,403	)		202,581
	Depreciation and amortization			4,958		3,568			414			1,483			—			10,423
	-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.

Quarterly_Results_of_Operation1

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Summary of Unaudited Quarterly Financial Data	The following table sets forth certain unaudited quarterly financial data for the years ended December 31 (in thousands, except per share amounts):
		First			Second			Third			Fourth			Total
	2014:00:00
	Net revenues	$	53,233		$	53,361		$	58,402		$	60,735		$	225,731
	Gross margin		22,792			22,662			25,550			26,116			97,120
	Consolidated net loss		(5,426	)		(4,932	)		(3,669	)		(43	)		(14,070	)
	Net income (loss) attributable to noncontrolling interest		(48	)		(97	)		5			(43	)		(183	)
	Net loss attributable to Vicor Corporation		(5,378	)		(4,835	)		(3,674	)		—			(13,887	)
	Net loss per share attributable to Vicor Corporation:
	Basic and diluted		(0.14	)		(0.13	)		(0.10	)		—			(0.36	)
		First			Second			Third			Fourth			Total
	2013:00:00
	Net revenues	$	41,946		$	46,865		$	55,091		$	55,258		$	199,160
	Gross margin		16,607			18,461			22,980			23,431			81,479
	Consolidated net loss		(4,986	)		(4,600	)		(898	)		(13,020	)		(23,504	)
	Net income attributable to noncontrolling interest		4			16			34			82			136
	Net loss attributable to Vicor Corporation		(4,990	)		(4,616	)		(932	)		(13,102	)		(23,640	)
	Net loss per share attributable to Vicor Corporation:
	Basic and diluted		(0.12	)		(0.12	)		(0.02	)		(0.34	)		(0.60	)

Significant_Accounting_Policie3

Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Customer	Customer	Customer
	Distributor
Revenue, Major Customer [Line Items]
Number of distributors	2
Gross deferred revenue	$1,769,000	$1,269,000
Gross deferred cost of revenue	808,000	516,000
Revenue recognized under multi-element	3.00%	3.00%	3.00%
Foreign currency losses, net	-196,000	-94,000	-46,000
Maturity period of cash and cash equivalents	Less than three months
Available-for-sale securities, failed auction, value	3,000,000
Number of customers accounted for trade account receivable	2	2
Number of customers	1	2	1
Cost of advertising	$1,832,000	$1,884,000	$1,910,000
Product warranty period	2 years
Percentage likelihood of tax benefit settlement	50.00%
Recognition period of non performance based stock options	5 years
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	14.70%		10.10%
Sales Revenue, Net [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	60.50%	59.50%	51.10%
Sales Revenue, Net [Member] | Hong Kong [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	20.20%	16.20%	12.50%
Sales Revenue, Net [Member] | CHINA | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	12.00%	11.30%
Sales Revenue, Net [Member] | TAIWAN, PROVINCE OF CHINA | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues			9.00%
Customer One [Member]
Revenue, Major Customer [Line Items]
Percentage of trade account receivable	14.90%	12.90%
Customer One [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues		10.90%
Customer Two [Member]
Revenue, Major Customer [Line Items]
Percentage of trade account receivable	11.60%	12.50%
Customer Two [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues		10.10%
Maximum [Member]
Revenue, Major Customer [Line Items]
Recognition period	12 months
Estimated useful life of intangible assets	20 years
Minimum [Member]
Revenue, Major Customer [Line Items]
Recognition period	6 months
Estimated useful life of intangible assets	3 years

Significant_Accounting_Policie4

Significant Accounting Policies - Computation of Basic and Diluted Loss Per Share (Detail) (USD $)	3 Months Ended							12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net loss attributable to Vicor Corporation	($3,674)	($4,835)	($5,378)	($13,102)	($932)	($4,616)	($4,990)	($13,887)	($23,640)	($4,077)
Denominator:
Denominator for basic loss per share-weighted average shares								38,569	39,195	41,811
Effect of dilutive securities:
Employee stock options								0	0	0
Denominator for diluted loss per share - adjusted weighted-average shares and assumed conversions								38,569	39,195	41,811
Basic loss per share								($0.36)	($0.60)	($0.10)
Diluted loss per share								($0.36)	($0.60)	($0.10)

Significant_Accounting_Policie5

Significant Accounting Policies - Computation of Basic and Diluted Loss Per Share (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Options to purchase shares of Common Stock not included in the calculation of net loss per share	1,895,675	1,989,248	545,345

StockBased_Compensation_and_Em2

Stock-Based Compensation and Employee Benefit Plans - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended		3 Months Ended		0 Months Ended
	Jun. 17, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 21, 2013	14-May-13	Dec. 31, 2014	Jun. 30, 2013	Nov. 11, 2011	Sep. 30, 2010	Dec. 31, 2010
	Participant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of Option		10 years
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
Incremental expenses		$365,000
Total unrecognized compensation cost		318,000					318,000
Stock-based compensation expense		1,634,000	2,450,000	1,244,000
Employee's compensation plan		The Company matches employee contributions to the plan at a rate of 50% up to the first 3% of an employee's compensation
Employee contributions		20.00%
Company contribution to the plan		877,000	825,000	813,000
Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options		58,250					58,250
Time-Based eligible Option exercise price		$6.29					$6.29
Total unrecognized compensation cost		940,000					940,000
Stock-based compensation expense		2,300,000
Time Based Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Time-Based eligible Option exercise price		$6.29					$6.29
Tranche One [Member] | Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		120.00%
Common stock sales price		$6.29
Tranche One [Member] | Time Based Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		120.00%
Tranche Two [Member] | Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		140.00%
Common stock sales price		$7.34
Tranche Three [Member] | Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		160.00%
Common stock sales price		$8.38
Tranche Four [Member] | Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		180.00%
Common stock sales price		$9.43
Tranche Five [Member] | Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		200.00%
Common stock sales price		$10.48
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employees pre-tax salary		1.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employees pre-tax salary		80.00%
Two Thousand Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		4,000,000					4,000,000
Non-qualified stock options										1,243,750
Common stock options awarded					70,552	150,000	150,355
Incremental expenses								208,000
Total unrecognized compensation cost		365,000					365,000
Immediate expense recognition								190,000
Exercise price of options awarded					$5.67	$5.35
Stock options, cancelled in period							129,028
Two Thousand Plan [Member] | Employees and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental expenses								625,000
Age of employees		62 years 6 months
Immediate expense recognition								450,000
Vicor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options granted to non-employees		85.00%
Non-qualified stock options		1,895,675	1,989,248				1,895,675
Common stock options awarded		343,650
Common stock sales price		$9.24
Total unrecognized compensation cost		1,369,000					1,369,000
Stock options, cancelled in period		310,182
Vicor options actually vest		78.00%
Annual forfeiture rate		8.00%	8.00%
Vicor options actually vest forfeiture			78.00%
Share exercisable		306,173	54,284	255,694			306,173
Weighted average exercise prices		$6.90	$9.72	$12.79			$6.90
Total Intrinsic value		751,000	15,000	2,000
Options Exercised		788,000	13,000	4,000
Fair value of stock options that vested		1,096,000	489,000	449,000
Compensation cost recognized over a weighted-average period		2 years 1 month 28 days
Expected recognized expenses, Year One		705,000					705,000
Expected recognized expenses, Year Two		399,000					399,000
Expected recognized expenses, Year Three		195,000					195,000
Expected recognized expenses, Year Four		62,000					62,000
Expected recognized expenses, Year Five		8,000					8,000
Weighted-average fair value		$5.50	$1.90	$2.47
2001 Picor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		20,000,000					20,000,000
Non-qualified stock options		0					0
Common stock options awarded									0
2007 VI Chip Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		12,000,000					12,000,000
Non-qualified stock options		0					0				2,984,250
Common stock options awarded									0
Total unrecognized compensation cost		621,000					621,000
Picor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options		9,870,067	9,404,367				9,870,067
Common stock options awarded		1,150,400
Common stock sales price		$0.41
Total unrecognized compensation cost		631,000					631,000
Stock options, cancelled in period		684,700
Maturity period of US Treasury Bond		7 years
Annual forfeiture rate		2.75%	2.75%
Picor options actually vest forfeiture		92.00%
Picor options actually vest			92.00%
Share exercisable		6,643,377	5,869,044	5,329,950			6,643,377
Weighted average exercise prices		$0.67	$0.69	$0.69			$0.67
Total Intrinsic value		0	146,000	279,000
Options Exercised			14,000	172,000
Fair value of stock options that vested		0	398,000	61,000
Compensation cost recognized over a weighted-average period		2 years 8 months 12 days
Expected recognized expenses, Year One		358,000					358,000
Expected recognized expenses, Year Two		140,000					140,000
Expected recognized expenses, Year Three		78,000					78,000
Expected recognized expenses, Year Four		43,000					43,000
Expected recognized expenses, Year Five		12,000					12,000
Weighted-average fair value		$0.19	$0.31	$0.32
Vi Chip Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options		10,715,000	10,744,250				10,715,000
Common stock options awarded		117,500
Common stock sales price		$1
Total unrecognized compensation cost		820,000					820,000
Stock options, cancelled in period		146,750
Maturity period of US Treasury Bond		7 years
Annual forfeiture rate		7.75%	7.00%
Chip options actually vest			80.00%
Chip options actually vest forfeiture		77.00%
Share exercisable		7,377,950	7,267,600	7,304,100			7,377,950
Weighted average exercise prices		$1	$1	$1			$1
Options Exercised		0	0	6,000
Compensation cost recognized over a weighted-average period		1 year 4 months 24 days
Expected recognized expenses, Year One		233,000					233,000
Expected recognized expenses, Year Two		192,000					192,000
Expected recognized expenses, Year Three		177,000					177,000
Expected recognized expenses, Year Four		149,000					149,000
Expected recognized expenses, Year Five		$69,000					$69,000
Weighted-average fair value		$0.02	$0.29	$0.46
Stock Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock purchase by non-employees		109,964					109,964

StockBased_Compensation_and_Em3

Stock-Based Compensation and Employee Benefit Plans - Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$1,634,000	$2,450,000	$1,244,000
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	183,000	163,000	45,000
Selling, General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	1,176,000	1,942,000	864,000
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$275,000	$345,000	$335,000

StockBased_Compensation_and_Em4

Stock-Based Compensation and Employee Benefit Plans - Weighted-Average Assumptions for Fair Value for Stock Options (Detail) (Non Performance-Based Stock Options [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Vicor [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	2.20%	1.20%	0.70%
Expected dividend yield			0.60%
Expected volatility	52.00%	39.00%	52.00%
Expected lives (years)	6 years 7 months 6 days
Vicor [Member] | Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	4 years 10 months 24 days
Vicor [Member] | Two Thousand Twelve [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	4 years 1 month 6 days
VI Chip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	2.30%	1.60%	1.20%
Expected volatility	41.00%	48.00%	50.00%
Expected lives (years)	6 years 6 months
VI Chip [Member] | Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	6 years 6 months
VI Chip [Member] | Two Thousand Twelve [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	6 years 6 months
Picor [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	2.20%	1.20%	1.20%
Expected volatility	42.00%	49.00%	50.00%
Expected lives (years)	6 years 6 months
Picor [Member] | Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	6 years 6 months
Picor [Member] | Two Thousand Twelve [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected lives (years)	6 years 6 months

StockBased_Compensation_and_Em5

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the 2000 Plan (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Exercised	-127,041
Vicor Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance	1,989,248
Options Outstanding, Granted	343,650
Options Outstanding, Forfeited and expired	-310,182
Options Outstanding, Exercised	-127,041
Options Outstanding, Ending balance	1,895,675
Options Outstanding, Exercisable	306,173	54,284	255,694
Options Outstanding, Vested or expected to vest	1,707,311
Weighted Average Exercise Price, Beginning balance	$7.71
Weighted Average Exercise Price, Granted	$9.24
Weighted Average Exercise Price, Forfeited and expired	$7.83
Weighted Average Exercise Price, Exercised	$6.20
Weighted Average Exercise Price, Ending balance	$8.01
Weighted Average Exercise Price, Exercisable	$6.90	$9.72	$12.79
Weighted Average Exercise Price, Vested or expected to vest	$7.97
Weighted-Average Remaining Contractual Life in Years, Outstanding	8 years 4 months 28 days
Weighted-Average Remaining Contractual Life in Years, Exercisable	7 years 10 months 6 days
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest	8 years 5 months 1 day
Aggregate Intrinsic Value, Outstanding	$7,796,000
Aggregate Intrinsic Value, Exercisable	1,642,000
Aggregate Intrinsic Value, Vested or expected to vest	$7,167,000

StockBased_Compensation_and_Em6

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the Picor Stock Option Plans (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Exercised	-127,041
Picor Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance	9,404,367
Options Outstanding, Granted	1,150,400
Options Outstanding, Forfeited and expired	-684,700
Options Outstanding, Exercised	0
Options Outstanding, Ending balance	9,870,067
Options Outstanding, Exercisable	6,643,377	5,869,044	5,329,950
Options Outstanding, Vested or expected to vest	9,749,482
Weighted Average Exercise Price, Beginning balance	$0.66
Weighted Average Exercise Price, Granted	$0.41
Weighted Average Exercise Price, Forfeited and expired	$0.73
Weighted Average Exercise Price, Exercised	$0
Weighted Average Exercise Price, Ending balance	$0.62
Weighted Average Exercise Price, Exercisable	$0.67	$0.69	$0.69
Weighted Average Exercise Price, Vested or expected to vest	$0.62
Weighted-Average Remaining Contractual Life in Years, Outstanding	5 years 10 months 21 days
Weighted-Average Remaining Contractual Life in Years, Exercisable	5 years 29 days
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest	5 years 10 months 10 days
Aggregate Intrinsic Value, Outstanding	$0
Aggregate Intrinsic Value, Exercisable	0
Aggregate Intrinsic Value, Vested or expected to vest	$0

StockBased_Compensation_and_Em7

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the VI Chip Stock Option Plans (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Exercised	-127,041
Vi Chip Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance	10,744,250
Options Outstanding, Granted	117,500
Options Outstanding, Forfeited and expired	-146,750
Options Outstanding, Exercised	0
Options Outstanding, Ending balance	10,715,000
Options Outstanding, Exercisable	7,377,950	7,267,600	7,304,100
Options Outstanding, Vested or expected to vest	10,423,793
Weighted Average Exercise Price, Beginning balance	$1
Weighted Average Exercise Price, Granted	$1
Weighted Average Exercise Price, Forfeited and expired	$1.01
Weighted Average Exercise Price, Exercised	$0
Weighted Average Exercise Price, Ending balance	$1
Weighted Average Exercise Price, Exercisable	$1	$1	$1
Weighted Average Exercise Price, Vested or expected to vest	$1
Weighted-Average Remaining Contractual Life in Years, Outstanding	3 years 9 months 29 days
Weighted-Average Remaining Contractual Life in Years, Exercisable	2 years 7 months 21 days
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest	3 years 9 months
Aggregate Intrinsic Value, Outstanding	$0
Aggregate Intrinsic Value, Exercisable	0
Aggregate Intrinsic Value, Vested or expected to vest	$0

StockBased_Compensation_and_Em8

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the VI Chip Stock Option Plans (Parenthetical) (Detail) (Vi Chip Plan [Member])	12 Months Ended
	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Granted, shares	117,500
Chief Executive Officer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Granted, shares	5,500,000

ShortTerm_and_LongTerm_Investm2

Short-Term and Long-Term Investments - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Amortized cost of securities	$3,700,000	$3,700,000	$6,820,000
Minimum period for which failed auction securities been in unrealized loss position		12 months
Estimated fair value of securities	3,272,000	3,272,000	5,651,000
Redemption, net	3,000,000
Gross unrealized losses	428,000	428,000	1,175,000
Aggregate credit loss	84,000	84,000	395,000	317,000	308,000
Failed Auction Securities [Member]
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Amortized cost of securities	3,000,000	3,000,000	6,000,000
Period for which failed auction securities been in unrealized loss position		Exceeds 12 months
Estimated fair value of securities	2,575,000	2,575,000	4,825,000
Gross unrealized losses	425,000	425,000	1,175,000
Aggregate credit loss	84,000	84,000
Aggregate temporary impairment loss		$341,000

ShortTerm_and_LongTerm_Investm3

Short-Term and Long-Term Investments - Summary of Available-for-Sale Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$3,700,000	$6,820,000
Gross Unrealized Gains		6,000
Gross unrealized losses	428,000	1,175,000
Estimated Fair Value	3,272,000	5,651,000
Failed Auction Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	3,000,000	6,000,000
Gross unrealized losses	425,000	1,175,000
Estimated Fair Value	2,575,000	4,825,000
Brokered Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	700,000	820,000
Gross Unrealized Gains		6,000
Gross unrealized losses	3,000
Estimated Fair Value	$697,000	$826,000

ShortTerm_and_LongTerm_Investm4

Short-Term and Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Available-for-sale Securities, Debt Maturities [Abstract]
Due in one year or less, Cost	$270
Due in two to ten years, Cost	430
Due in ten to twenty years, Cost	0
Due in twenty to forty years, Cost	3,000
Cost	3,700	6,820
Due in one year or less, Estimated Fair Value	270
Due in two to ten years, Estimated Fair Value	427
Due in ten to twenty years, Estimated Fair Value	0
Due in twenty to forty years, Estimated Fair Value	2,575
Estimated Fair Value	$3,272	$5,651

ShortTerm_and_LongTerm_Investm5

Short-Term and Long-Term Investments - Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities [Abstract]
Balance at the beginning of the period	$395	$317	$308
Reductions for securities sold during the period	-272	-7
Additions for the amount related to credit loss for which other-than-temporary impairment was not previously recognized	-39	85	9
Balance at the end of the period	$84	$395	$317

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$3,272	$5,651
Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,575	4,825
Recurring [Member] | Short-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	270	463
Recurring [Member] | Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,575	4,825
Recurring [Member] | Long-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	427	363
Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	11,207	12,407
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	11,207	12,407
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	270	463
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	427	363
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	$2,575	$4,825

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Percent of credit loss	2.80%
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	$100,000

Fair_Value_Measurements_Quanti

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$3,272	$5,651
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$2,575
Valuation Technique	Discounted cash flow
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Cumulative Probability of Earning Maximum Rate Until Maturity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	Cumulative probability of earning the maximum rate until maturity
Weighted Average Interest Rate	0.02%
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Cumulative Probability of Principal Return Prior to Maturity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	Cumulative probability of principal return prior to maturity
Weighted Average Interest Rate	93.74%
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Cumulative Probability of Default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	Cumulative probability of default
Weighted Average Interest Rate	6.24%
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Liquidity Risk Premium [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	Liquidity risk premium
Weighted Average Interest Rate	5.00%
Failed Auction Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Recovery Rate in Default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	Recovery rate in default
Weighted Average Interest Rate	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) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Balance at the beginning of the period	$4,825
Redemptions	-3,000
Credit gains on available for sales securities included in Other income (expense), net	311
Gain included in Other comprehensive income (loss)	439
Balance at the end of the period	$2,575

Inventories_Summary_of_Invento

Inventories - Summary of Inventories (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$18,252	$19,744
Work-in-process	3,339	3,979
Finished goods	4,737	5,973
Net balance	$26,328	$29,696

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciation expense	$9,833,000	$10,180,000	$10,546,000
Capital expenditure commitments	$841,000
Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization period	39 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciation and amortization period	3 years

Property_Plant_and_Equipment_P

Property, Plant and Equipment - Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Land	$2,089	$2,089
Buildings and improvements	43,800	43,083
Machinery and equipment	228,663	224,481
Furniture and fixtures	5,905	6,047
Construction in-progress and deposits	2,568	1,327
Property, plant and equipment, gross, total	283,025	277,027
Accumulated depreciation and amortization	-245,638	-236,935
Net balance	$37,387	$40,092

Other_Investments_Additional_I

Other Investments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Agreement
Variable Interest Entity [Line Items]
Ownership interest in investment	27.00%	27.00%
Number of supply agreements with GWS	2
Purchase of components under agreement	$2,146,000	$1,959,000	$2,087,000
GWS [Member]
Variable Interest Entity [Line Items]
Company owed GWS	170,000	152,000
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]
Gross investment in non-voting convertible preferred stock	$5,000,000	$5,000,000

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets - Schedule of Patent Cost and Other Asset (Detail) (Patents [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Patent costs	$2,721	$3,170
Accumulated amortization	-1,689	-2,007
Finite-lived intangible assets, net	$1,032	$1,163

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Patent renewal fees		$25,000	$38,000
Amortization expense		170,000	264,000	314,000
Impairment of goodwill	2,012,000			2,012,000
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Future amortization expense from patent assets held for 2015		143,000
Future amortization expense from patent assets held for 2016		130,000
Future amortization expense from patent assets held for 2017		124,000
Future amortization expense from patent assets held for 2018		108,000
Future amortization expense from patent assets held for 2019		$102,000

Severance_Charges_Additional_I

Severance Charges - Additional Information (Detail) (USD $)	6 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Severance charges	$2,207,000	$1,904,000
Other restructuring charges		$303,000

Severance_Charges_Summary_of_A

Severance Charges - Summary of Activity Related to Severance Charges by Segment (Detail) (USD $)	6 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Restructuring Reserve, Beginning Balance		$49,000
Charges	2,207,000	1,904,000
Payments		0
Restructuring Reserve, Ending Balance	$1,904,000	$1,904,000

Product_Warranties_Product_War

Product Warranties - Product Warranty Activity (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Guarantees [Abstract]
Balance at the beginning of the period	$283	$364	$572
Accruals for warranties for products sold in the period	281	327	439
Fulfillment of warranty obligations	-350	-297	-554
Revisions of estimated obligations	-10	-111	-93
Balance at the end of the period	$204	$283	$364

Stockholders_Equity_Additional

Stockholders' Equity - Additional information (Detail) (USD $)	0 Months Ended		12 Months Ended
	Apr. 22, 2013	Mar. 07, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares accepted	1,341,575	1,931,513	0	0	0
Aggregate consideration for Common Stock	$6,708,000	$10,392,000
Tender offer expiration date			22-Apr-13
Common Stock repurchased as per November plan						30,000,000
Stock repurchase program amount available			8,541,000	8,541,000
Cash dividends paid to the Company			3,738,000	1,569,000	1,222,000
Cash dividends paid to outside shareholders			162,000	531,000	378,000
Common Stock were issued upon the exercise of stock options			127,041
Subsidiaries [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash dividends on subsidiary common stock			$3,900,000	$2,100,000	$1,600,000
Vicor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance			14,719,889

Other_Income_Expense_Net_Compo

Other Income (Expense), Net - Components of Other Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income and Expenses [Abstract]
Interest income	$80	$97	$136
Foreign currency losses, net	-196	-94	-46
Gain on disposal of equipment	22	26	33
Credit gains (losses) on available for sale securities	311	-78	-9
Other	51	51	80
Total other income (expense), net	$268	$2	$194

Income_Taxes_Schedule_of_Recon

Income Taxes - Schedule of Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory federal tax rate	-34.00%	-34.00%	-34.00%
State income taxes, net of federal income tax benefit	0.80%	1.10%	-9.40%
Tax credits	-12.40%	-8.10%	0.60%
U.S. manufacturing deduction		1.70%	-3.80%
Permanent items	0.40%	0.60%	2.20%
Book income attributable to noncontrolling interest	-0.60%	0.40%	6.80%
Foreign rate differential and deferred items	-0.30%	-0.20%	0.10%
Increase (decrease) in tax reserves	-3.70%	-0.10%	0.30%
Increase in valuation allowance	46.90%	53.30%	84.50%
Other		0.10%	-0.70%
Effective income tax rate	-2.90%	14.80%	46.60%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Assets Liabilities [Line Items]
Tax benefit recognized		$0
Benefit for income taxes	552,000	-425,000	3,039,000	1,207,000
Research tax credit carry forward extension period		2 years
Federal research tax credit recorded		549,000
Unremitted earnings of international subsidiaries		2,940,000
Unrecognized deferred tax liability		185,000
Valuation allowance, deferred tax assets		25,818,000	20,214,000
Deferred tax assets valuation allowance increase			10,241,000
Amount generate in cash refund		1,600,000
Increases in equity of realization of deferred tax assets		3,024,000
Accrued interest		1,254,000	2,072,000	1,506,000	1,405,000
Net interest (benefit) expense		32,000	-28,000	32,000
Potential payment of interest		181,000	149,000
Net tax benefit refunded from completion of examination	$17,000
Minimum [Member]
Deferred Tax Assets Liabilities [Line Items]
Income tax examination period		3 years
Maximum [Member]
Deferred Tax Assets Liabilities [Line Items]
Income tax examination period		7 years
Domestic Tax Authority [Member]
Deferred Tax Assets Liabilities [Line Items]
Federal net operating loss carryforwards expired		2033

Income_Taxes_Schedule_of_Domes

Income Taxes - Schedule of Domestic and Foreign Components of Income (Loss) Before Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Domestic	($14,223)	($20,466)	($3,109)
Foreign	-272	1	518
Loss before income taxes	($14,495)	($20,465)	($2,591)

Income_Taxes_Schedule_of_Compo

Income Taxes - Schedule of Components of Provision (Benefit) for Income Taxes (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal		($690)	($1,848)	$920
State		147	284	425
Foreign		124	112	231
Current, Total		-419	-1,452	1,576
Deferred:
Federal		-6	4,491	-369
Provision (benefit) for income taxes	$552	($425)	$3,039	$1,207

Income_Taxes_Schedule_of_Signi

Income Taxes - Schedule of Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Research and development tax credit carryforwards	$10,756	$8,754
Net operating loss carryforwards	3,560	2,497
Stock-based compensation	3,465	3,048
Inventory reserves	3,024	2,687
Vacation accrual	1,821	1,645
Investment tax credit carryforwards	1,446	1,367
Foreign tax credits	1,405
Accrued severance	525
Alternative minimum tax credit carryforward	340	340
Deferred revenue	178	279
Unrealized loss on investments	131	399
Warranty reserves	65	88
Bad debt reserves	59	65
Capital loss carryforward		680
Other	446	428
Total deferred tax assets	27,221	22,277
Less: Valuation allowance for deferred tax assets	-25,818	-20,214
Net deferred tax assets	1,403	2,063
Deferred tax liabilities:
Depreciation	-176	-918
Prepaid expenses	-755	-598
Patent amortization	-365	-416
Unremitted Vicor Custom Power earnings	-329	-335
Total deferred tax liabilities	-1,625	-2,267
Net deferred tax liabilities	($222)	($204)

Income_Taxes_Schedule_of_Recon1

Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning Balance	$2,072	$1,506	$1,405
Additions based on tax provisions related to the current year	161	566	134
Reductions for tax positions of prior years	-967		-33
Lapse of statute	-12
Unrecognized tax benefits, Ending Balance	$1,254	$2,072	$1,506

Commitments_and_Contingencies_1

Commitments and Contingencies - Summary of Future Minimum Rental Commitments under Non-Cancelable Operating Leases (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$1,514
2016	811
2017	412
2018	139
2019 and thereafter	$120

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended			3 Months Ended		12 Months Ended
	Mar. 26, 2009	Nov. 14, 2008	Feb. 22, 2007	Dec. 31, 2012	Dec. 31, 2006	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 02, 2009
Commitments and Contingencies Disclosure [Abstract]
Rent expense						$1,824,000	$1,820,000	$1,677,000
Legal settlement cost			50,000,000
Reimbursed by the insurance carriers			12,800,000
Gain (loss) from the litigation-related settlements				1,975,000	-37,200,000			1,975,000
Jury awarded in damages to the Company		17,300,000
Reduction in jury award									4,000,000
Affirming the award	13,300,000
Prejudgment interest	3,179,000
Insurance carriers total	16,479,000
Insurance carriers on cash payment								$1,975,000

Segment_Information_Additional

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Entity
Segment Reporting [Abstract]
Number of entities comprising operating segment	6

Segment_Information_Significan

Segment Information - Significant Segment Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net revenues	$60,735	$58,402	$53,361	$53,233	$55,258	$55,091	$46,865	$41,946	$225,731	$199,160	$218,507
Income (loss) from operations									-14,763	-20,467	-2,785
Total assets	155,542				165,640				155,542	165,640	202,581
Depreciation and amortization									9,805	10,008	10,423
Operating Segments [Member] | BBU [Member]
Segment Reporting Information [Line Items]
Net revenues									184,224	163,013	179,919
Income (loss) from operations									15,499	12,062	28,114
Total assets	151,923				126,585				151,923	126,585	97,507
Depreciation and amortization									4,711	6,185	4,958
Operating Segments [Member] | VI Chip [Member]
Segment Reporting Information [Line Items]
Net revenues									34,701	35,333	38,083
Income (loss) from operations									-29,015	-28,204	-27,409
Total assets	17,677				21,370				17,677	21,370	21,105
Depreciation and amortization									3,265	3,232	3,568
Operating Segments [Member] | Picor [Member]
Segment Reporting Information [Line Items]
Net revenues									15,570	10,416	9,724
Income (loss) from operations									-407	-3,326	-2,786
Total assets	5,691				4,308				5,691	4,308	5,365
Depreciation and amortization									410	407	414
Operating Segments [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									-840	-999	-704
Total assets	75,758				81,364				75,758	81,364	119,007
Depreciation and amortization									1,419	184	1,483
Eliminations [Member]
Segment Reporting Information [Line Items]
Net revenues									-8,764	-9,602	-9,219
Total assets	($95,507)				($67,987)				($95,507)	($67,987)	($40,403)

Quarterly_Results_of_Operation2

Quarterly Results of Operations (Unaudited) - Summary of Unaudited Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$60,735	$58,402	$53,361	$53,233	$55,258	$55,091	$46,865	$41,946	$225,731	$199,160	$218,507
Gross margin	26,116	25,550	22,662	22,792	23,431	22,980	18,461	16,607	97,120	81,479	91,651
Consolidated net loss	-43	-3,669	-4,932	-5,426	-13,020	-898	-4,600	-4,986	-14,070	-23,504	-3,798
Net income (loss) attributable to noncontrolling interest	-43	5	-97	-48	82	34	16	4	-183	136	279
Net loss attributable to Vicor Corporation		($3,674)	($4,835)	($5,378)	($13,102)	($932)	($4,616)	($4,990)	($13,887)	($23,640)	($4,077)
Net loss per share attributable to Vicor Corporation:
Basic and diluted		($0.10)	($0.13)	($0.14)	($0.34)	($0.02)	($0.12)	($0.12)	($0.36)	($0.60)

Quarterly_Results_of_Operation3

Quarterly Results of Operations (Unaudited) - Additional Information (Detail) (USD $)	3 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Income tax valuation allowance against certain deferred tax assets	$10,132,000

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts (Detail) (Allowance for Doubtful Accounts [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$198,000	$292,000	$266,000
Charge to Costs and Expenses	66,000	255,000	37,000
Other Charges, Deductions	-81,000	-349,000	-11,000
Balance at End of Period	$183,000	$198,000	$292,000