Vicor (VICR) 10-K 8 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 29, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	VICR
Entity Registrant Name	VICOR CORP
Entity Central Index Key	751,978
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 199,714,000
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		27,035,328
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		11,758,218

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 62,980	$ 55,187
Short-term investments		270
Accounts receivable, less allowance of $171 in 2015 and $183 in 2014	25,982	28,431
Inventories, net	23,442	26,328
Deferred tax assets		107
Other current assets	3,102	3,155
Total current assets	115,506	113,478
Long-term deferred tax assets	15
Long-term investments, net	2,866	3,002
Property, plant and equipment, net	37,450	37,387
Other assets	1,708	1,675
Total assets	157,545	155,542
Current liabilities:
Accounts payable	7,470	7,932
Accrued compensation and benefits	8,349	8,663
Accrued expenses	2,568	3,178
Accrued severance charges	195	1,904
Income taxes payable	31	41
Deferred revenue	1,988	1,439
Total current liabilities	20,601	23,157
Long-term deferred revenue	468	637
Contingent consideration obligation	144
Long-term income taxes payable	192	867
Deferred income taxes	55	329
Total liabilities	$ 21,460	$ 24,990
Commitments and contingencies (Note 16)
Vicor Corporation stockholders' equity:
Preferred Stock, $.01 par value, 1,000,000 shares authorized; no shares issued
Additional paid-in capital	$ 174,337	$ 171,901
Retained earnings	99,685	94,758
Accumulated other comprehensive loss	(577)	(471)
Treasury stock at cost: 11,671,486 shares in 2015 and 2014	(138,927)	(138,927)
Total Vicor Corporation stockholders' equity	135,031	127,772
Noncontrolling interest	1,054	2,780
Total equity	136,085	130,552
Total liabilities and equity	157,545	155,542
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	$ 395	$ 393

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) $ in Thousands	Dec. 31, 2015USD ($)Vote$ / sharesshares	Dec. 31, 2014USD ($)Vote$ / sharesshares
Accounts receivable, allowance | $	$ 171	$ 183
Preferred Stock, par value | $ / shares	$ 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 | Vote	10	10
Common Stock, par value | $ / shares	$ 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 | Vote	1	1
Common Stock, par value | $ / shares	$ 0.01	$ 0.01
Common Stock, shares authorized	62,000,000	62,000,000
Common Stock, shares issued	38,705,564	38,580,480
Common Stock, shares outstanding	27,034,078	26,908,994

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net revenues	$ 220,194	$ 225,731	$ 199,160
Cost of revenues	120,676	128,611	117,681
Gross margin	99,518	97,120	81,479
Operating expenses:
Selling, general and administrative	58,313	68,197	60,737
Research and development	41,472	41,479	39,848
Severance and other charges		2,207	1,361
Total operating expenses	99,785	111,883	101,946
Loss from operations	(267)	(14,763)	(20,467)
Other income (expense), net:
Total unrealized gains (losses) on available-for-sale securities, net	(49)	750	(54)
Portion of gains (losses) recognized in other comprehensive income (loss)	61	(439)	(24)
Net credit gains (losses) recognized in earnings	12	311	(78)
Other income (expense), net	13	(43)	80
Total other income (expense), net	25	268	2
Loss before income taxes	(242)	(14,495)	(20,465)
Less: (Benefit) provision for income taxes	(401)	(425)	3,039
Gain from sale of equity method investment, net of tax	5,000
Consolidated net income (loss)	5,159	(14,070)	(23,504)
Less: Net income (loss) attributable to noncontrolling interest	232	(183)	136
Net income (loss) attributable to Vicor Corporation	$ 4,927	$ (13,887)	$ (23,640)
Net income (loss) per common share attributable to Vicor Corporation:
Basic	$ 0.13	$ (0.36)	$ (0.60)
Diluted	$ 0.13	$ (0.36)	$ (0.60)
Shares used to compute net income (loss) per common share attributable to Vicor Corporation:
Basic	38,754	38,569	39,195
Diluted	39,146	38,569	39,195

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)		$ 5,159	$ (14,070)	$ (23,504)
Foreign currency translation losses, net of tax benefit	[1]	(52)	(410)	(496)
Unrealized gains (losses) on available-for-sale securities, net of tax	[2]	(59)	429	17
Other comprehensive income (loss)		(111)	19	(479)
Consolidated comprehensive income (loss)		5,048	(14,051)	(23,983)
Less: Comprehensive income (loss) attributable to noncontrolling interest		227	(219)	71
Comprehensive income (loss) attributable to Vicor Corporation		$ 4,821	$ (13,832)	$ (24,054)
[1]	Net of tax benefit of $0, $0 and $(378) for 2015, 2014, and 2013, 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, 2015, 2014, and 2013. Therefore, there is no income tax benefit recognized for the three years ended December 31, 2015.

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Foreign currency translation gains (losses), tax provision (benefit)	$ 0	$ 0	$ (378,000)
Recognized income tax provision (benefit)	$ 0	$ 0	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Consolidated net income (loss)	$ 5,159	$ (14,070)	$ (23,504)
Adjustments to reconcile consolidated net income (loss) to net cash provided by (used for) operating activities:
Depreciation and amortization	9,142	9,805	10,008
Gain from sale of equity method investment	(5,000)
Gain from disposition of consolidated subsidiary	(28)
Stock-based compensation expense	1,782	1,634	2,450
Decrease in long-term income taxes payable	(675)	(472)	(155)
Deferred income taxes	(183)	18	4,491
Decrease in long-term deferred revenue	(139)	(139)	(139)
Gain on disposal of equipment	(60)	(22)	(26)
(Benefit) provision for doubtful accounts	(18)	66
Credit (gain) loss on available for sale securities	(12)	(311)	78
Change in current assets and liabilities, net	1,499	5,682	2,107
Net cash provided by (used for) operating activities	11,467	2,191	(4,690)
Investing activities:
Sales and maturities of investments	360	3,460	1,024
Purchases of investments		(340)
Additions to property, plant and equipment	(9,090)	(7,128)	(6,179)
Proceeds from sale of equity method investment	5,000
Deconsolidation of subsidiary	(392)
Proceeds from sale of equipment	60	22	26
(Increase) decrease in other assets	(204)	(43)	49
Net cash used for investing activities	(4,266)	(4,029)	(5,080)
Financing activities:
Purchases of Common Stock			(17,100)
Proceeds from issuance of Common Stock	820	788	27
Acquisition of noncontrolling interest	(216)
Noncontrolling interest dividends paid		(162)	(531)
Reversal of excess tax benefit of share-based compensation			(451)
Net cash provided by (used for) financing activities	604	626	(18,055)
Effect of foreign exchange rates on cash	(12)	60	(390)
Net increase (decrease) in cash and cash equivalents	7,793	(1,152)	(28,215)
Cash and cash equivalents at beginning of period	55,187	56,339	84,554
Cash and cash equivalents at end of period	62,980	55,187	56,339
Change in assets and liabilities, excluding effects of disposition of consolidated subsidiary:
Accounts receivable	2,201	(1,151)	(821)
Inventories, net	1,880	3,202	33
Other current assets	(111)	1,029	(1,647)
Accounts payable and accrued liabilities	(1,301)	300	4,580
Accrued severance charges	(1,709)	1,855	49
Income taxes payable	(10)	26	(321)
Deferred revenue	549	421	234
Change in current assets and liabilities, net	1,499	5,682	2,107
Supplemental disclosures:
Cash paid during the year for income taxes, net of refunds	$ 675	$ (1,529)	$ (61)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Vicor Corporation Stockholders' Equity [Member]	Noncontrolling Interest [Member]	Class B Common Stock [Member]
Beginning Balance at Dec. 31, 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)
Net income (loss)	(23,504)			(23,640)			(23,640)	136
Other comprehensive loss	(479)				(414)		(414)	(65)
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
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
Net income (loss)	(14,070)			(13,887)			(13,887)	(183)
Other comprehensive loss	19				55		55	(36)
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)
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
Disposition of consolidated subsidiary	(1,742)		(5)				(5)	(1,737)
Sales of Common Stock	820	2	818				820
Acquisition of noncontrolling interest	(360)		(144)				(144)	(216)
Stock-based compensation expense	1,782		1,782				1,782
Other	7		7				7
Net settlement stock option exercises	(22)		(22)				(22)
Net income (loss)	5,159			4,927			4,927	232
Other comprehensive loss	(111)				(106)		(106)	(5)
Components of comprehensive income, net of tax
Net income (loss)	5,159			4,927			4,927	232
Other comprehensive income (loss)	(111)				(106)		(106)	(5)
Total comprehensive income (loss)	5,048						4,821	227
Total comprehensive income (loss)	5,048						4,821	227
Ending Balance at Dec. 31, 2015	$ 136,085	$ 395	$ 174,337	$ 99,685	$ (577)	$ (138,927)	$ 135,031	$ 1,054	$ 118

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. DESCRIPTION OF BUSINESS Vicor Corporation (the “Company” or “Vicor”) designs, develops, manufactures, and markets modular power components and power systems for converting, regulating and controlling electric current. 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 Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
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 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, 2015, the Company had gross deferred revenue of approximately $2,042,000 and gross deferred cost of revenues of approximately $882,000 under agreements with stocking distributors ($1,769,000 and $808,000, respectively, as of December 31, 2014). 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 2015, 2014, and 2013, 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 ($161,000), ($196,000), and ($94,000) in 2015, 2014, and 2013, 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, 2015, 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, 2015, 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, 2015, one customer accounted for approximately 21.9% of trade account receivables. As of December 31, 2014, two customers accounted for approximately 14.9% and 11.6% of trade account receivables, respectively. Credit losses have consistently been within management’s expectations. During 2015, one customer accounted for approximately 16.2% of net revenues. 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. International sales, based on customer location, as a percentage of total net revenues, were approximately 59.6% in 2015, 60.5% in 2014, and 59.5% in 2013. Net revenues from customers in Hong Kong and China accounted for approximately 21.8% and 12.4%, respectively, of total net revenues in 2015, approximately 20.2% and 12.0%, respectively, of total net revenues in 2014 and approximately 16.2% and 11.3%, respectively, of total net revenues in 2013. 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. Advertising expense The cost of advertising is expensed as incurred. The Company incurred $1,762,000, $1,832,000, and $1,884,000 in advertising costs during 2015, 2014 and 2013, respectively. Product warranties The Company generally offers a two-year warranty for all of its products, though it is party to a limited number of supply agreements with certain customers contractually committing the Company to warranty and indemnification requirements exceeding those to which the Company has been exposed in the past. 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 income (loss) per common share The Company computes basic net income (loss) per share using the weighted average number of common shares outstanding and diluted net income (loss) 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 net income (loss) per share for the years ended December 31 (in thousands, except per share amounts): 2015 2014 2013 Numerator: Net income (loss) attributable to Vicor Corporation $ 4,927 $ (13,887 ) $ (23,640 ) Denominator: Denominator for basic net income (loss) per share-weighted average shares (1) 38,754 38,569 39,195 Effect of dilutive securities: Employee stock options (2) 392 — — Denominator for diluted net income (loss) per share — adjusted weighted-average shares and assumed conversions (3) 39,146 38,569 39,195 Basic net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) Diluted net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) (1) Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding. (2) Options to purchase 238,792, 1,895,675, and 1,989,248 shares of Common Stock in 2015, 2014, and 2013, respectively, were not included in the calculation of net income (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. For December 31, 2015, based on newly adopted accounting guidance discussed below, all deferred tax assets and liabilities are classified as noncurrent. Previously, deferred tax assets and liabilities were 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 November 2015, the Financial Accounting Standards Board (“FASB”) issued new guidance for the classification of deferred taxes. The new standard requires that deferred tax assets and liabilities be classified as noncurrent on the balance sheet rather than being separated into current and noncurrent. This new guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted and the standard may be applied either retrospectively or on a prospective basis to all deferred tax assets and liabilities. The Company early adopted the new guidance during fiscal year 2015 on a prospective basis. Accordingly, all deferred taxes have been classified as noncurrent on the December 31, 2015 Consolidated Balance Sheets and prior periods were not retrospectively adjusted. The adoption of this new guidance did not have a material impact on the Company’s financial position. In July 2015, the FASB issued new guidance for inventory accounting, which will require companies to measure in scope inventory at the lower of cost or net realizable value. Current guidance requires an entity to measure inventory at the lower of cost or market. The new guidance does not apply to inventory that is measured using last-in, first-out (“LIFO”) or retail inventory methods. The guidance applies to all other inventory, which includes inventory that is measured using first-in, first-out (“FIFO”), which the Company employs, or average cost methods. The new guidance will be effective for the Company on January 1, 2017, and is to be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The Company has not yet determined the impact the new guidance will have on its consolidated financial statements and related disclosures. In May 2014, the 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 now be on January 1, 2018, as on July 9, 2015, the FASB voted to defer the effective date of the new standard by one year. 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 the standard will have on its ongoing financial reporting.

Stock-Based Compensation and Em

Stock-Based Compensation and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
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”) 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”) 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”) 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, is being 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 $370,000 as of December 31, 2015. 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 44,500 of these Performance-Based Eligible Options remain outstanding as of December 31, 2015. 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, 2015, 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 $279,000 as of December 31, 2015. 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 VI Chip Corporation. 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, 2015 and, accordingly, expense has been recorded through that date. The unrecognized compensation expense for these performance-based options was approximately $485,000 as of December 31, 2015. 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): 2015 2014 2013 Cost of revenues $ 230 $ 183 $ 163 Selling, general and administrative 1,246 1,176 1,942 Research and development 306 275 345 Total stock-based compensation $ 1,782 $ 1,634 $ 2,450 The decrease in stock-based compensation expense in 2015 and 2014 compared to 2013 were 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: 2015 2014 2013 Risk-free interest rate 2.0 % 2.2 % 1.2 % Expected dividend yield — — — Expected volatility 51 % 52 % 39 % Expected lives (years) 7.2 6.6 4.9 VI Chip: 2015 2014 2013 Risk-free interest rate 2.1 % 2.3 % 1.6 % Expected dividend yield — — — Expected volatility 37 % 41 % 48 % Expected lives (years) 6.5 6.5 6.5 Picor: 2015 2014 2013 Risk-free interest rate 1.9 % 2.2 % 1.2 % Expected dividend yield — — — Expected volatility 41 % 42 % 49 % Expected lives (years) 6.5 6.5 6.5 Risk-free interest rate: Vicor Picor and VI Chip Expected dividend yield: Vicor Picor and VI Chip Expected volatility: Vicor Picor VI Chip Expected term: Vicor Picor and VI Chip 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 Picor VI Chip Vicor Stock Options A summary of the activity under Vicor’s stock option plans as of December 31, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 1,895,675 $ 8.07 Granted 194,561 $ 12.51 Forfeited and expired (117,085 ) $ 9.30 Exercised (125,084 ) $ 6.44 Outstanding on December 31, 2015 1,848,067 $ 8.57 7.64 $ 2,637 Exercisable on December 31, 2015 565,861 $ 7.24 7.25 $ 1,269 Vested or expected to vest as of December 31, 2015 (1) 1,778,075 $ 8.51 7.64 $ 2,580 (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, 2014 and 2013, the Company had options exercisable for 306,173 and 54,284 shares respectively, for which the weighted average exercise prices were $6.90 and $9.72, respectively. During the years ended December 31, 2015, 2014, and 2013 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 $928,000, $751,000, and $15,000, respectively. The total amount of cash received by the Company from options exercised in 2015, 2014, and 2013, was $805,000, $788,000, and $13,000, respectively. The total grant-date fair value of stock options that vested during the years ended December 31, 2015, 2014, and 2013 was approximately $1,194,000, $1,096,000, and $489,000, respectively. As of December 31, 2015, there was $1,393,000 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 1.8 years for those awards. The expense will be recognized as follows: $726,000 in 2016, $397,000 in 2017, $186,000 in 2018, $71,000 in 2019, and $13,000 in 2020. The weighted-average fair value of Vicor options granted was $6.76, $5.50, and $1.90, in 2015, 2014, and 2013, respectively. Picor Stock Options A summary of the activity under the 2001 Picor Plan as of December 31, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 9,870,067 $ 0.62 Granted 82,000 $ 1.09 Forfeited and expired (8,000 ) $ 0.75 Exercised (219,000 ) $ 0.76 Outstanding on December 31, 2015 9,725,067 $ 0.62 5.01 $ 4,520 Exercisable on December 31, 2015 8,053,490 $ 0.64 4.48 $ 3,594 Vested or expected to vest as of December 31, 2015 (1) 9,668,334 $ 0.62 4.99 $ 4,488 (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, 2014 and 2013, Picor had options exercisable for 6,643,377 and 5,869,044 shares, respectively, for which the weighted average exercise prices were $0.67 and $0.69, respectively. During the years ended December 31, 2015, and 2013, the total intrinsic value of Picor options exercised was $72,000 and $146,000, respectively. There were no Picor options exercised in 2014. The total amounts of cash received by Picor from options exercised in 2015 and 2013 was $14,000 in both years. The total grant-date fair value of stock options vesting during the years ended December 31, 2015, 2014, and 2013 was approximately $39,000, $0, and $398,000, respectively. As of December 31, 2015, there was $307,000 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 2.6 years for all Picor awards. The expense will be recognized as follows: $148,000 in 2016, $86,000 in 2017, $51,000 in 2018, $19,000 in 2019, and $3,000 in 2020. The weighted-average fair value of Picor options granted was $0.48 in 2015, $0.19 in 2014, and $0.31 in 2013. VI Chip Stock Options A summary of the activity under the 2007 VI Chip Plan as of December 31, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 10,715,000 $ 1.00 Granted 82,500 $ 1.00 Forfeited and expired (699,000 ) $ 1.00 Exercised (1,000 ) $ 1.00 Outstanding on December 31, 2015 (1) 10,097,500 $ 1.00 2.87 $ — Exercisable on December 31, 2015 7,042,600 $ 1.00 1.75 $ — Vested or expected to vest as of December 31, 2015 (2) 9,821,129 $ 1.00 2.80 $ — (1) Of the total VI Chip options outstanding on December 31, 2015, 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, 2014 and 2013, VI Chip had options exercisable for 7,377,950 and 7,267,600 shares, respectively, for which the weighted average exercise price was $1.00. The total intrinsic value of VI Chip options exercised in 2015 was zero. The total amount of cash received by VI Chip from options exercised in 2015 was $1,000. There were no VI Chip options exercised in 2014 and 2013. As of December 31, 2015, there was $589,000 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 3.0 years for all VI Chip awards. The expense will be recognized as follows: $192,000 in 2016, $178,000 in 2017, $150,000 in 2018, and $69,000 in 2019. The weighted-average fair value of VI Chip options granted was $0.01, $0.02, and $0.29 in 2015, 2014, and 2013, 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 $854,000, $877,000, and $825,000 in 2015, 2014, and 2013, 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, 2015, 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.

Short-Term and Long-Term Invest

Short-Term and Long-Term Investments	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Short-Term and Long-Term Investments	4. SHORT-TERM AND LONG-TERM INVESTMENTS As of December 31, 2015 and 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, 2015 and 2014, the Company held one auction rate security that had experienced failed auctions of $3,000,000 at par value, which was purchased through and is held by a broker-dealer affiliate of Bank of America, N.A. (the “Failed Auction Security”). The Failed Auction Security held by the Company is Aaa/AA+ rated by the major credit rating agencies, 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, 2015, 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, 2015. The following is a summary of available-for-sale securities (in thousands): December 31, 2015 Cost Gross Gross Estimated Fair Failed Auction Security $ 3,000 $ — $ 474 $ 2,526 Brokered certificates of deposit 340 — — 340 $ 3,340 $ — $ 474 $ 2,866 December 31, 2014 Cost Gross Gross Estimated Fair Failed Auction Security $ 3,000 $ — $ 425 $ 2,575 Brokered certificates of deposit 700 — 3 697 $ 3,700 $ — $ 428 $ 3,272 As of December 31, 2015 and 2014, the Failed Auction Security had been in an unrealized loss position for greater than 12 months. The amortized cost and estimated fair value of available-for-sale securities on December 31, 2015, by contractual maturities, are shown below (in thousands): Cost Estimated Due in two to ten years $ 340 $ 340 Due in ten to twenty years — — Due in twenty to forty years 3,000 2,526 $ 3,340 $ 2,866 Based on the fair value measurements described in Note 5, the fair value of the Failed Auction Security on December 31, 2015, with a par value of $3,000,000, was estimated by the Company to be approximately $2,526,000. The gross unrealized loss of $474,000 on the Failed Auction Security consists of two types of estimated loss: an aggregate credit loss of $72,000 and an aggregate temporary impairment of $402,000. 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 security, 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): 2015 2014 2013 Balance at the beginning of the period $ 84 $ 395 $ 317 Reductions for securities sold during the period — (272 ) (7 ) Additions (reductions) for the amount related to credit loss for which other-than-temporary impairment was not previously recognized (12 ) (39 ) 85 Balance at the end of the period $ 72 $ 84 $ 395 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, 2015
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 and liabilities measured at fair value on a recurring basis included the following as of December 31, 2015 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 10,412 $ — $ — $ 10,412 Long-term investments: Failed Auction Security — — 2,526 2,526 Brokered certificates of deposit — 340 — 340 Liabilities: Contingent consideration obligation — — (144 ) (144 ) Assets measured at fair value on a recurring basis included the following as of December 31, 2014 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 11,207 $ — $ — $ 11,207 Short-term investments: Brokered certificates of deposit — 270 — 270 Long-term investments: Failed Auction Securities — — 2,575 2,575 Brokered certificates of deposit — 427 — 427 The Company has classified its contingent consideration obligation as Level 3 because the fair value for this liability was determined using unobservable inputs. The liability was based on estimated sales of legacy products over the period of royalty payments at the royalty rate (see Note 9), discounted using the Company’s estimated cost of capital. The Company has classified its brokered certificates of deposit as Level 2 because the fair value for these investments was 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, 2015, 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, 2015. 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 2.4%; the rate of return required by investors to own this type of security 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 this type of security 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 Rate 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 arm’s 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, 2015 are as follows (dollars in thousands): Fair Valuation Unobservable Input Weighted Failed Auction Security $ 2,526 Discounted Cumulative probability of earning the maximum rate until maturity 0.03 % Cumulative probability of principal return prior to maturity 93.73 % Cumulative probability of default 6.24 % Liquidity risk premium 5.00 % Recovery rate in default 40.00 % The change in the estimated fair value calculated for the investment valued on a recurring basis utilizing Level 3 inputs (i.e., the Failed Auction Security) for the year ended December 31, 2015 was as follows (in thousands): Balance at the beginning of the period $ 2,575 Credit gain on available- for- sale security included in Other income (expense), net 12 Loss included in Other comprehensive income (loss) (61 ) Balance at the end of the period $ 2,526 The change in the estimated fair value calculated for the liability valued on a recurring basis utilizing Level 3 inputs (i.e., the Contingent consideration obligation) for the year ended December, 31, 2015 was as follows (in thousands): Balance at the beginning of the period $ — Obligation incurred upon acquisition of noncontrolling interest (see Note 9) (144 ) Balance at the end of the period $ (144 ) There were no transfers between Level 1 and Level 2 of the fair value hierarchy during the year ended December, 31, 2015.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventories	6. INVENTORIES Inventories as of December 31 were as follows (in thousands): 2015 2014 Raw materials $ 16,257 $ 18,252 Work-in-process 2,879 3,339 Finished goods 4,306 4,737 Net balance $ 23,442 $ 26,328

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 Land $ 2,089 $ 2,089 Buildings and improvements 44,647 43,800 Machinery and equipment 231,305 228,663 Furniture and fixtures 5,652 5,905 Construction in-progress and deposits 3,839 2,568 287,532 283,025 Accumulated depreciation and amortization (250,082 ) (245,638 ) Net balance $ 37,450 $ 37,387 Depreciation expense for the years ended December 31, 2015, 2014 and 2013 was approximately $9,028,000, $9,833,000, and $10,180,000 respectively. As of December 31, 2015, the Company had approximately $1,089,000 of capital expenditure commitments.

Other Investments

Other Investments	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Other Investments	8. OTHER INVESTMENTS In September 2015, Intersil Corporation (“Intersil”) acquired, through a statutory merger, Great Wall Semiconductor Corporation (“GWS”), in which the Company held non-voting convertible preferred stock. GWS and its subsidiary designed and sold semiconductors, conducted research and development activities, and developed and licensed patents. A director of the Company was the founder, Chairman of the Board, President and Chief Executive Officer (“CEO”), as well as the majority voting shareholder, of GWS. The Company accounted for its investment in GWS under the equity method. The Company determined, while GWS was a variable interest entity, the Company was not the primary beneficiary. The key factors in the Company’s assessment were that the CEO of GWS had: (i) the power to direct the activities of GWS that most significantly impact its economic performance, and (ii) an obligation to absorb losses or the right to receive benefits from GWS, respectively, that could potentially be significant to GWS. At the time of the merger transaction, the Company’s gross investment totaled $4,999,719. However, during the fourth quarter of 2008, the Company determined a decline in value judged to be other-than-temporary had occurred and, as such, the investment’s recorded value on the Consolidated Balance Sheet, as of December 31, 2008, was reduced to zero. Management’s decision to reduce the remaining investment balance to zero at that time was based on GWS’ continued operating losses, the impact of the global economic crisis on the current and short-term outlook for its operations, a negative working capital position as of December 31, 2008, and a valuation based on discounted cash flows. Under the terms of the merger agreement between GWS and Intersil, and in accordance with the terms of the shareholder agreement under which the Company made its investments, all preferred stock was redeemed at full preference value (i.e., purchased for cash equal to the original investment amount). This redemption was effected through the exchange of a share of preferred stock for (a) the right to receive the preference value in cash upon surrender of the preferred shares and (b) the non-transferable right to receive certain cash payments as additional consideration, after a period of 16 months, associated with (i) the release by Intersil of some or all of the $2,625,000 portion of total consideration held in escrow by Intersil for potential funding of indemnification and related obligations made by GWS and its selling shareholders and (ii) additional consideration of up to $4,000,000, payable in the event Intersil achieved certain revenue goals related to GWS products. Immediately after the closing of the merger transaction, the Company received the full preference value, equal to its gross investment in GWS. Because the net investment on the Company’s Consolidated Balance Sheet had a value of zero, the full preference value was recorded as a gain from sale of equity method investment in the third quarter of 2015. Just prior to the merger, the Company also received, as a dividend from GWS, shares of an entity in which GWS held an investment. Such shares were deemed by the Company to have a value of zero on the date of receipt. While the Company’s shares of preferred stock were never converted into shares of non-voting common stock, as provided for in the terms of the shareholder agreement under which the Company made its investment, the proportionate share of the contingent amounts described above was calculated assuming such a conversion, resulting in a pro forma The Company and GWS were parties to an intellectual property cross-licensing agreement, a license agreement (see below), and two supply agreements, under which the Company purchased certain components from GWS. Intersil, through the merger transaction, has assumed all of GWS’ rights and obligations under these agreements. Company purchases from GWS totaled approximately $1,662,000 for the nine months ended September 30, 2015, the approximate date of the sale, and $2,146,000 and $1,959,000 in 2014 and 2013, respectively. The Company owed GWS zero and approximately $170,000 as of December 31, 2015 and December 31, 2014, respectively. During the second quarter of 2009, the Company entered into a license agreement with GWS in which the Company paid $500,000 to obtain certain rights to several GWS semiconductor devices. This amount was fully amortized, on a straight-line basis, over four years.

Noncontrolling Interest Transac

Noncontrolling Interest Transactions	12 Months Ended
	Dec. 31, 2015
Noncontrolling Interest [Abstract]
Noncontrolling Interest Transactions	9. NONCONTROLLING INTEREST TRANSACTIONS On December 28, 2015, the Company sold its 49% ownership interest in Aegis Power Systems, Inc. (“APS”) to the 51% noncontrolling interest holder for approximately $1,698,000. The amount of the proceeds approximated the Company’s share of the net equity of APS, resulting in a gain of approximately $28,000, which was recorded in Other income (expense), net in the accompanying Consolidated Statements of Operations. As a result of the transaction, cash of approximately $2,090,000 and other net assets of approximately $1,317,000 of APS were fully deconsolidated from the Company’s consolidated balance sheet as of December 31, 2015. After the sale, APS will operate independently from the Company, and may purchase the Company’s products going forward, on an arms-length basis. Also on December 28, 2015, the Company acquired the noncontrolling interest holder’s 18% ownership interest in Mission Power Solutions, Inc. (“MPS”) for approximately $216,000, which equaled the noncontrolling interest holder’s share of the net equity of MPS. This transaction was achieved through a statutory merger of MPS with and into an existing Vicor Custom Power wholly-owned subsidiary, Northwest Power, Inc. (“NPI”). In addition to the payment noted above, the selling principal will be eligible to receive quarterly royalty payments through June 30, 2021 equal to a percentage of the revenue generated by the sale of certain MPS legacy products to be manufactured by NPI going forward. The estimated obligation for total future royalties, recorded as Contingent consideration obligation in the accompanying Consolidated Balance Sheets, is approximately $144,000 as of December 31, 2015. The acquisition of the noncontrolling interest holder’s 18% ownership interest was accounted for as an equity transaction, and therefore, the noncontrolling interest balance in equity for this subsidiary was reduced to zero. The excess of the acquisition amount, which is inclusive of the cash paid and the value of the contingent consideration obligation, over the noncontrolling interest balance in equity, was recorded as a charge to additional paid-in capital. The respective noncontrolling interest holders of APS and MPS served as key employees of each company prior to the transactions described above.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	10. INTANGIBLE ASSETS Patent costs, which are included in other assets in the accompanying balance sheets, as of December 31 were as follows (in thousands): 2015 2014 Patent costs $ 2,525 $ 2,721 Accumulated amortization (1,583 ) (1,689 ) $ 942 $ 1,032 Definite lived intangible assets, such as patent rights, are amortized and tested for impairment if a triggering event occurs. Patent renewal fees were $64,000 and $25,000 in 2015 and 2014, respectively. Amortization expense was approximately $145,000, $170,000 and $264,000 in 2015, 2014 and 2013, respectively. The estimated future amortization expense from patent assets held as of December 31, 2015, is projected to be $133,000, $127,000, $111,000, $105,000 and $100,000, in fiscal years 2016, 2017, 2018, 2019, and 2020, respectively.

Severance and Other Charges

Severance and Other Charges	12 Months Ended
	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Severance and Other Charges	11. SEVERANCE AND OTHER CHARGES In July 2014, the Company’s management authorized the consolidation of the manufacturing of its Westcor division products, of the BBU segment, announcing its intent to transfer 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 related liability is presented as “Accrued severance charges” in the Consolidated Balance Sheets. A summary of the activity related to the accrued severance charges, is as follows (in thousands): Balance as of December 31, 2014 $ 1,904 Payments (1,709 ) Balance as of December 31, 2015 $ 195

Product Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Product Warranties	12. PRODUCT WARRANTIES Product warranty activity for the years ended December 31 was as follows (in thousands): 2015 2014 2013 Balance at the beginning of the period $ 204 $ 283 $ 364 Accruals for warranties for products sold in the period 715 281 327 Fulfillment of warranty obligations (334 ) (350 ) (297 ) Revisions of estimated obligations — (10 ) (111 ) Balance at the end of the period $ 585 $ 204 $ 283

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	13. 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 2015, 2014, and 2013. On December 31, 2015 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, 2015, one subsidiary paid a total of $250,000 in cash dividends, all of which was paid to the Company. 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. Dividends paid to outside shareholders of our subsidiaries are accounted for as a reduction in noncontrolling interest. On December 31, 2015, 2014, and 2013 there were 14,594,805, 14,719,889, and 14,846,930, respectively, 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, 2015
Other Income and Expenses [Abstract]
Other Income (Expense), Net	14. 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): 2015 2014 2013 Interest income $ 47 $ 80 $ 97 Foreign currency losses, net (161 ) (196 ) (94 ) Gain on disposal of equipment 60 22 26 Credit gains (losses) on available for sale securities 12 311 (78 ) Other 67 51 51 $ 25 $ 268 $ 2

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	15. 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 may include discrete items, principally related to tax credits, increases or decreases in tax reserves, tax provision vs. tax return differences and accrued interest for potential liabilities. The reconciliation of the federal statutory rate on the loss before income taxes and before the gain from sale of equity method investment to the effective income tax rate for the years ended December 31 is as follows: 2015 2014 2013 Statutory federal tax rate (34.0 %) (34.0 %) (34.0 %) State income taxes, net of federal income tax benefit 46.4 0.8 1.1 Tax credits 29.9 (12.4 ) (8.1 ) Book income attributable to noncontrolling interest 47.0 (0.6 ) 0.4 Permanent items 21.2 0.4 0.6 Decrease in tax reserves (248.6 ) (3.7 ) (0.1 ) Foreign rate differential and deferred items (18.2 ) (0.3 ) (0.2 ) Capital gain on sale to noncontrolling interest 237.8 — — Decrease in unremitted Vicor Custom Power earnings (108.7 ) — — (Decrease) increase in valuation allowance (138.4 ) 46.9 53.3 U.S. manufacturing deduction — — 1.7 Other (0.1 ) — 0.1 (165.7 %) (2.9 %) 14.8 % In 2015 and 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. In 2015, the Company entered into voluntary disclosure agreements with several states. As a result, the Company recognized a tax benefit of approximately $555,000 as a discrete item in the fourth quarter of 2015 for the release of tax reserves. In addition, in connection with the Company’s sale of its 49% interest in APS, recognized as a capital gain, the related deferred tax liability for unremitted earnings of $274,000 was reversed and recorded as a deferred tax benefit in the fourth quarter of 2015 (see Note 9). 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. 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 and before the gain from sale of equity method investment for the years ended December 31 include the following components (in thousands): 2015 2014 2013 Domestic $ 1,373 $ (14,223 ) $ (20,466 ) Foreign (1,615 ) (272 ) 1 $ (242 ) $ (14,495 ) $ (20,465 ) Significant components of the provision (benefit) for income taxes for the years ended December 31 are as follows (in thousands): 2015 2014 2013 Current: Federal $ 144 $ (690 ) $ (1,848 ) State (473 ) 147 284 Foreign 111 124 112 (218 ) (419 ) (1,452 ) Deferred: Federal (274 ) (6 ) 4,491 Foreign 91 — — (183 ) (6 ) 4,491 $ (401 ) $ (425 ) $ 3,039 As discussed in Note 8, the Company recorded a gain from equity method investment in the third quarter of 2015 for cash consideration received equal to its gross investment in GWS of $4,999,719 for the full preference value of its non-voting convertible preferred stock upon GWS’ acquisition by Intersil, as the value of the investment for financial reporting purposes was zero. For income tax purposes, though, the tax basis of the investment was $4,999,719 at the time of the redemption as it was not previously deducted for tax purposes and, therefore, there was no gain or loss on the transaction for income tax purposes. The Company intends to continue to reinvest certain of its foreign earnings indefinitely. Accordingly, no U.S. income taxes have been provided for approximately $841,000 of unremitted earnings of international subsidiaries. As of December 31, 2015, the amount of unrecognized deferred tax liability on these earnings was $37,000. Significant components of the Company’s deferred tax assets and liabilities as of December 31 were as follows (in thousands): 2015 2014 Deferred tax assets: Research and development tax credit carryforwards $ 12,503 $ 10,756 Stock-based compensation 3,993 3,465 Net operating loss carryforwards 3,393 3,560 Inventory reserves 2,979 3,024 Vacation accrual 1,768 1,821 Investment tax credit carryforwards 1,399 1,446 Alternative minimum tax credit carryforward 340 340 Warranty reserves 202 65 Deferred revenue 192 178 Unrealized loss on investments 149 131 Bad debt reserves 58 59 Accrued severance 35 525 Foreign tax credits — 1,405 Other 700 446 Total deferred tax assets 27,711 27,221 Less: Valuation allowance for deferred tax assets (25,862 ) (25,818 ) Net deferred tax assets 1,849 1,403 Deferred tax liabilities: Depreciation (787 ) (176 ) Prepaid expenses (713 ) (755 ) Patent amortization (334 ) (365 ) Unremitted Vicor Custom Power earnings (55 ) (329 ) Total deferred tax liabilities (1,889 ) (1,625 ) Net deferred tax liabilities $ (40 ) $ (222 ) As of December 31, 2015, the Company has a valuation allowance of approximately $25,862,000 primarily against all 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) then recent cumulative losses and the Company’s projection of continued losses into 2014; (3) while the Company had 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 subsequently 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, 2015. As a result, management believes a full valuation allowance against all domestic net deferred tax assets is warranted as of December 31, 2015. 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, 2015, 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 $3,216,000 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 2016 for state purposes and in 2022 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 2016 through 2035. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): 2015 2014 2013 Balance on January 1 $ 1,254 $ 2,072 $ 1,506 Additions based on tax provisions related to the current year 120 161 566 Reductions for tax positions of prior years — (967 ) — Settlements (480 ) — — Lapse of statute (64 ) (12 ) — Balance on December 31 $ 830 $ 1,254 $ 2,072 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, 2015, 2014, and 2013 of $830,000, $1,254,000, and $2,072,000, 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, 2015, 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, 2015, 2014, and 2013, the Company recognized approximately $21,000, $32,000, and ($28,000), respectively, in net interest (benefit) expense. As of December 31, 2015 and 2014, the Company had accrued approximately $24,000 and $181,000, 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 2014 and 2007 through 2014, 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. 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. The statute of limitations for the tax authorities in Italy to file an assessment, if any, for tax year 2009 expired on December 31, 2015. 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, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. 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 2016 $ 1,314 2017 762 2018 338 2019 213 2020 and thereafter 119 Rent expense was approximately $1,902,000, $1,824,000 and $1,820,000 in 2015, 2014 and 2013, 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 the 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 the 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, the terms of which were not disclosed. On September 16, 2011, the U.S. District Court for the Eastern District of Texas (the “Texas Court”) 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 (the “ ‘290 patent”), which was issued on that day. As with SynQor’s original complaint, the amended complaint alleges the Company’s products, including but not limited to the Company’s unregulated bus converters used in intermediate bus architecture power supply systems, infringe 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 Texas 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 Texas Court’s claim construction ruling. On March 31, 2014, the Texas 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 “ ‘021 patent”), which is one of four related patents at question in the Texas Action. The Texas Court has yet to rule on these motions. On October 23, 2014, the Texas 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 Texas Court. On February 6, 2015, SynQor filed a motion to consolidate the Company’s and Cisco’s cases for trial, which was subsequently denied. On March 13, 2015, the U.S. Court of Appeals for the Federal Circuit in Washington, D.C. Circuit issued a ruling invalidating certain claims of U.S. Patent No. 7,072,190 (the “ ‘190 patent”) asserted by SynQor against the Company. Challenges to the validity of the remaining claims relating to the ‘190 patent, and to the remaining patents asserted by SynQor against the Company, remain pending before the U.S. Patent and Trademark Office and in the Texas Action. On March 26, 2015, the Texas Court scheduled pre-trial conferences for September 15, 2015, for Cisco’s case and January 13, 2016, for the Company’s case. On April 20, 2015, the Patent Trial and Appeal Board of the United States Patent and Trademark Office (the “PTAB”) issued a decision upholding the validity of all of the claims of SynQor’s U.S. Patent No. 7,564,702 (the “ ‘702 patent”), another of the power converter patents included in the claims asserted against the Company in the Texas Action. On May 20, 2015, the Company filed a request for rehearing concerning that decision. The PTAB has not ruled on that request. On May 5, 2015, the PTAB issued a decision invalidating all of the asserted claims of the ‘021 patent. On June 10, 2015, SynQor filed a request for rehearing concerning that decision. The PTAB has not ruled on that request. The Company has received no notice from the Texas Court regarding the timing of rulings on the Company’s summary judgment motions. On June 19, 2015, the Texas Court issued an order scheduling a jury trial in SynQor’s patent infringement action against Cisco beginning on November 30, 2015. SynQor’s patent infringement allegations against Cisco include allegations that Cisco is using certain parts supplied by the Company in infringing circuits. On October 5, 2015, the Texas Court issued an order denying a motion by Cisco seeking a stay of SynQor’s case against Cisco pending the resolution of matters concerning the asserted SynQor patents before the PTAB. On November 20, 2015, SynQor and Cisco informed the Texas Court they had reached a confidential settlement of SynQor’s case against Cisco. On November 24, 2015, a Magistrate Judge of the Texas Court issued an order staying SynQor’s case against the Company pending the resolution of matters concerning the asserted SynQor patents before the PTAB. SynQor has filed a motion seeking reconsideration of that order, and that request is still pending. The Company continues to believe 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, including such use by Cisco. 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, however, the Company cannot estimate the amount of possible loss or range of possible loss at this time. 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 will have a material adverse impact on the Company’s financial position or results of operations.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Information	17. 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 DC-DC converters and configurable products, and also includes the entities comprising Vicor Custom Power, the BBU operations of VJCL, and the operations of the Company’s Westcor division through its closure in December 2014. Since the two noncontrolling interest Vicor Custom Power transactions occurred on December 28, 2015, as discussed in Note 9, the following segment information includes the full year operating results for APS and MPS in 2015, but not total assets for APS as of December 31, 2015. The VI Chip segment includes VI Chip Corporation, which designs, develops, manufactures, and markets many of the Company’s advanced power component 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. The Picor segment develops these products for use in the Company’s BBU and VI Chip modules, to be sold as complements to the Company’s BBU and VI Chip products, or for sale to third parties for separate (i.e., stand-alone) 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) 2015: Net revenues $ 173,064 $ 36,688 $ 17,304 $ — $ (6,862 ) $ 220,194 Income (loss) from operations 21,743 (21,040 ) (290 ) (680 ) — (267 ) Total assets 170,939 15,577 5,369 81,824 (116,164 ) 157,545 Depreciation and amortization 4,538 2,740 442 1,422 — 9,142 2014: 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: 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 (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 Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	18. 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 2015: Net revenues $ 64,017 $ 56,119 $ 48,664 $ 51,394 $ 220,194 Gross margin 28,891 26,510 21,286 22,831 99,518 Consolidated net income (loss) 3,442 771 2,609 (1,663 ) 5,159 Net income (loss) attributable to noncontrolling interest 71 (34 ) 106 89 232 Net income (loss) attributable to Vicor Corporation 3,371 805 2,503 (1,752 ) 4,927 Net income (loss) per share attributable to Vicor Corporation: Basic and diluted 0.09 0.02 0.06 (0.05 ) 0.13 First Second Third Fourth Total 2014: 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 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 )

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	VICOR CORPORATION SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS Years ended December 31, 2015, 2014 and 2013 Description Balance at Charge to Costs and Other Charges, Balance at Allowance for doubtful accounts: Year ended: December 31, 2015 $ 183,000 $ 18,000 $ (30,000 ) $ 171,000 December 31, 2014 198,000 66,000 (81,000 ) 183,000 December 31, 2013 292,000 255,000 (349,000 ) 198,000 (1) Reflects uncollectible accounts written off, net of recoveries.

Significant Accounting Polici28

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
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 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, 2015, the Company had gross deferred revenue of approximately $2,042,000 and gross deferred cost of revenues of approximately $882,000 under agreements with stocking distributors ($1,769,000 and $808,000, respectively, as of December 31, 2014). 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 2015, 2014, and 2013, 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 ($161,000), ($196,000), and ($94,000) in 2015, 2014, and 2013, 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, 2015, 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, 2015, 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, 2015, one customer accounted for approximately 21.9% of trade account receivables. As of December 31, 2014, two customers accounted for approximately 14.9% and 11.6% of trade account receivables, respectively. Credit losses have consistently been within management’s expectations. During 2015, one customer accounted for approximately 16.2% of net revenues. 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. International sales, based on customer location, as a percentage of total net revenues, were approximately 59.6% in 2015, 60.5% in 2014, and 59.5% in 2013. Net revenues from customers in Hong Kong and China accounted for approximately 21.8% and 12.4%, respectively, of total net revenues in 2015, approximately 20.2% and 12.0%, respectively, of total net revenues in 2014 and approximately 16.2% and 11.3%, respectively, of total net revenues in 2013. 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.
Advertising expense	Advertising expense The cost of advertising is expensed as incurred. The Company incurred $1,762,000, $1,832,000, and $1,884,000 in advertising costs during 2015, 2014 and 2013, respectively.
Product warranties	Product warranties The Company generally offers a two-year warranty for all of its products, though it is party to a limited number of supply agreements with certain customers contractually committing the Company to warranty and indemnification requirements exceeding those to which the Company has been exposed in the past. 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 income (loss) per common share	Net income (loss) per common share The Company computes basic net income (loss) per share using the weighted average number of common shares outstanding and diluted net income (loss) 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 net income (loss) per share for the years ended December 31 (in thousands, except per share amounts): 2015 2014 2013 Numerator: Net income (loss) attributable to Vicor Corporation $ 4,927 $ (13,887 ) $ (23,640 ) Denominator: Denominator for basic net income (loss) per share-weighted average shares (1) 38,754 38,569 39,195 Effect of dilutive securities: Employee stock options (2) 392 — — Denominator for diluted net income (loss) per share — adjusted weighted-average shares and assumed conversions (3) 39,146 38,569 39,195 Basic net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) Diluted net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) (1) Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding. (2) Options to purchase 238,792, 1,895,675, and 1,989,248 shares of Common Stock in 2015, 2014, and 2013, respectively, were not included in the calculation of net income (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. For December 31, 2015, based on newly adopted accounting guidance discussed below, all deferred tax assets and liabilities are classified as noncurrent. Previously, deferred tax assets and liabilities were 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 November 2015, the Financial Accounting Standards Board (“FASB”) issued new guidance for the classification of deferred taxes. The new standard requires that deferred tax assets and liabilities be classified as noncurrent on the balance sheet rather than being separated into current and noncurrent. This new guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted and the standard may be applied either retrospectively or on a prospective basis to all deferred tax assets and liabilities. The Company early adopted the new guidance during fiscal year 2015 on a prospective basis. Accordingly, all deferred taxes have been classified as noncurrent on the December 31, 2015 Consolidated Balance Sheets and prior periods were not retrospectively adjusted. The adoption of this new guidance did not have a material impact on the Company’s financial position. In July 2015, the FASB issued new guidance for inventory accounting, which will require companies to measure in scope inventory at the lower of cost or net realizable value. Current guidance requires an entity to measure inventory at the lower of cost or market. The new guidance does not apply to inventory that is measured using last-in, first-out (“LIFO”) or retail inventory methods. The guidance applies to all other inventory, which includes inventory that is measured using first-in, first-out (“FIFO”), which the Company employs, or average cost methods. The new guidance will be effective for the Company on January 1, 2017, and is to be applied prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. The Company has not yet determined the impact the new guidance will have on its consolidated financial statements and related disclosures. In May 2014, the 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 now be on January 1, 2018, as on July 9, 2015, the FASB voted to defer the effective date of the new standard by one year. 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 the standard will have on its ongoing financial reporting.

Significant Accounting Polici29

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Computation Of Basic And Diluted Net Income (Loss) Per Share	The following table sets forth the computation of basic and diluted net income (loss) per share for the years ended December 31 (in thousands, except per share amounts): 2015 2014 2013 Numerator: Net income (loss) attributable to Vicor Corporation $ 4,927 $ (13,887 ) $ (23,640 ) Denominator: Denominator for basic net income (loss) per share-weighted average shares (1) 38,754 38,569 39,195 Effect of dilutive securities: Employee stock options (2) 392 — — Denominator for diluted net income (loss) per share — adjusted weighted-average shares and assumed conversions (3) 39,146 38,569 39,195 Basic net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) Diluted net income (loss) per share $ 0.13 $ (0.36 ) $ (0.60 ) (1) Denominator represents weighted average number of Common Shares and Class B Common Shares outstanding. (2) Options to purchase 238,792, 1,895,675, and 1,989,248 shares of Common Stock in 2015, 2014, and 2013, respectively, were not included in the calculation of net income (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.

Stock-Based Compensation and 30

Stock-Based Compensation and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Stock-Based Compensation Expense	Stock-based compensation expense for the years ended December 31 was as follows (in thousands): 2015 2014 2013 Cost of revenues $ 230 $ 183 $ 163 Selling, general and administrative 1,246 1,176 1,942 Research and development 306 275 345 Total stock-based compensation $ 1,782 $ 1,634 $ 2,450
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: 2015 2014 2013 Risk-free interest rate 2.0 % 2.2 % 1.2 % Expected dividend yield — — — Expected volatility 51 % 52 % 39 % Expected lives (years) 7.2 6.6 4.9 VI Chip: 2015 2014 2013 Risk-free interest rate 2.1 % 2.3 % 1.6 % Expected dividend yield — — — Expected volatility 37 % 41 % 48 % Expected lives (years) 6.5 6.5 6.5 Picor: 2015 2014 2013 Risk-free interest rate 1.9 % 2.2 % 1.2 % Expected dividend yield — — — Expected volatility 41 % 42 % 49 % Expected lives (years) 6.5 6.5 6.5
Vicor Plan [Member]
Stock-Based Compensation Expense	A summary of the activity under Vicor’s stock option plans as of December 31, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 1,895,675 $ 8.07 Granted 194,561 $ 12.51 Forfeited and expired (117,085 ) $ 9.30 Exercised (125,084 ) $ 6.44 Outstanding on December 31, 2015 1,848,067 $ 8.57 7.64 $ 2,637 Exercisable on December 31, 2015 565,861 $ 7.24 7.25 $ 1,269 Vested or expected to vest as of December 31, 2015 (1) 1,778,075 $ 8.51 7.64 $ 2,580 (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, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 9,870,067 $ 0.62 Granted 82,000 $ 1.09 Forfeited and expired (8,000 ) $ 0.75 Exercised (219,000 ) $ 0.76 Outstanding on December 31, 2015 9,725,067 $ 0.62 5.01 $ 4,520 Exercisable on December 31, 2015 8,053,490 $ 0.64 4.48 $ 3,594 Vested or expected to vest as of December 31, 2015 (1) 9,668,334 $ 0.62 4.99 $ 4,488 (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, 2015 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data): Options Weighted- Weighted- Aggregate Outstanding on December 31, 2014 10,715,000 $ 1.00 Granted 82,500 $ 1.00 Forfeited and expired (699,000 ) $ 1.00 Exercised (1,000 ) $ 1.00 Outstanding on December 31, 2015 (1) 10,097,500 $ 1.00 2.87 $ — Exercisable on December 31, 2015 7,042,600 $ 1.00 1.75 $ — Vested or expected to vest as of December 31, 2015 (2) 9,821,129 $ 1.00 2.80 $ — (1) Of the total VI Chip options outstanding on December 31, 2015, 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.

Short-Term and Long-Term Inve31

Short-Term and Long-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 Cost Gross Gross Estimated Fair Failed Auction Security $ 3,000 $ — $ 474 $ 2,526 Brokered certificates of deposit 340 — — 340 $ 3,340 $ — $ 474 $ 2,866 December 31, 2014 Cost Gross Gross Estimated Fair Failed Auction Security $ 3,000 $ — $ 425 $ 2,575 Brokered certificates of deposit 700 — 3 697 $ 3,700 $ — $ 428 $ 3,272
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, 2015, by contractual maturities, are shown below (in thousands): Cost Estimated Due in two to ten years $ 340 $ 340 Due in ten to twenty years — — Due in twenty to forty years 3,000 2,526 $ 3,340 $ 2,866
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): 2015 2014 2013 Balance at the beginning of the period $ 84 $ 395 $ 317 Reductions for securities sold during the period — (272 ) (7 ) Additions (reductions) for the amount related to credit loss for which other-than-temporary impairment was not previously recognized (12 ) (39 ) 85 Balance at the end of the period $ 72 $ 84 $ 395

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis included the following as of December 31, 2015 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 10,412 $ — $ — $ 10,412 Long-term investments: Failed Auction Security — — 2,526 2,526 Brokered certificates of deposit — 340 — 340 Liabilities: Contingent consideration obligation — — (144 ) (144 ) Assets measured at fair value on a recurring basis included the following as of December 31, 2014 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 11,207 $ — $ — $ 11,207 Short-term investments: Brokered certificates of deposit — 270 — 270 Long-term investments: Failed Auction Securities — — 2,575 2,575 Brokered certificates of deposit — 427 — 427
Quantitative Information about Level 3 Fair Value Measurements	Quantitative information about Level 3 fair value measurements as of December 31, 2015 are as follows (dollars in thousands): Fair Valuation Unobservable Input Weighted Failed Auction Security $ 2,526 Discounted Cumulative probability of earning the maximum rate until maturity 0.03 % Cumulative probability of principal return prior to maturity 93.73 % Cumulative probability of default 6.24 % Liquidity risk premium 5.00 % Recovery rate in default 40.00 %
Change in Estimated Fair Values Calculated for Investment Valued on Recurring Basis Utilizing Level 3 Inputs	The change in the estimated fair value calculated for the investment valued on a recurring basis utilizing Level 3 inputs (i.e., the Failed Auction Security) for the year ended December 31, 2015 was as follows (in thousands): Balance at the beginning of the period $ 2,575 Credit gain on available- for- sale security included in Other income (expense), net 12 Loss included in Other comprehensive income (loss) (61 ) Balance at the end of the period $ 2,526
Change in Estimated Fair Value Calculated for Liability Valued on Recurring Basis Utilizing Level 3 Inputs	The change in the estimated fair value calculated for the liability valued on a recurring basis utilizing Level 3 inputs (i.e., the Contingent consideration obligation) for the year ended December, 31, 2015 was as follows (in thousands): Balance at the beginning of the period $ — Obligation incurred upon acquisition of noncontrolling interest (see Note 9) (144 ) Balance at the end of the period $ (144 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories as of December 31 were as follows (in thousands): 2015 2014 Raw materials $ 16,257 $ 18,252 Work-in-process 2,879 3,339 Finished goods 4,306 4,737 Net balance $ 23,442 $ 26,328

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment as of December 31 were as follows (in thousands): 2015 2014 Land $ 2,089 $ 2,089 Buildings and improvements 44,647 43,800 Machinery and equipment 231,305 228,663 Furniture and fixtures 5,652 5,905 Construction in-progress and deposits 3,839 2,568 287,532 283,025 Accumulated depreciation and amortization (250,082 ) (245,638 ) Net balance $ 37,450 $ 37,387

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 Patent costs $ 2,525 $ 2,721 Accumulated amortization (1,583 ) (1,689 ) $ 942 $ 1,032

Severance and Other Charges (Ta

Severance and Other Charges (Tables)	12 Months Ended
	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Summary of Activity Related to Accrued Severance Charges	A summary of the activity related to the accrued severance charges, is as follows (in thousands): Balance as of December 31, 2014 $ 1,904 Payments (1,709 ) Balance as of December 31, 2015 $ 195

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Product Warranty Activity	Product warranty activity for the years ended December 31 was as follows (in thousands): 2015 2014 2013 Balance at the beginning of the period $ 204 $ 283 $ 364 Accruals for warranties for products sold in the period 715 281 327 Fulfillment of warranty obligations (334 ) (350 ) (297 ) Revisions of estimated obligations — (10 ) (111 ) Balance at the end of the period $ 585 $ 204 $ 283

Other Income (Expense), Net (Ta

Other Income (Expense), Net (Tables)	12 Months Ended
	Dec. 31, 2015
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): 2015 2014 2013 Interest income $ 47 $ 80 $ 97 Foreign currency losses, net (161 ) (196 ) (94 ) Gain on disposal of equipment 60 22 26 Credit gains (losses) on available for sale securities 12 311 (78 ) Other 67 51 51 $ 25 $ 268 $ 2

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Federal Statutory Rate on Loss before Income Taxes and before Gain from Sale of Equity Method Investment Rate to Effective Income Tax Rate	The reconciliation of the federal statutory rate on the loss before income taxes and before the gain from sale of equity method investment to the effective income tax rate for the years ended December 31 is as follows: 2015 2014 2013 Statutory federal tax rate (34.0 %) (34.0 %) (34.0 %) State income taxes, net of federal income tax benefit 46.4 0.8 1.1 Tax credits 29.9 (12.4 ) (8.1 ) Book income attributable to noncontrolling interest 47.0 (0.6 ) 0.4 Permanent items 21.2 0.4 0.6 Decrease in tax reserves (248.6 ) (3.7 ) (0.1 ) Foreign rate differential and deferred items (18.2 ) (0.3 ) (0.2 ) Capital gain on sale to noncontrolling interest 237.8 — — Decrease in unremitted Vicor Custom Power earnings (108.7 ) — — (Decrease) increase in valuation allowance (138.4 ) 46.9 53.3 U.S. manufacturing deduction — — 1.7 Other (0.1 ) — 0.1 (165.7 %) (2.9 %) 14.8 %
Schedule of Domestic and Foreign Components of Income (Loss) Before Income Taxes and before the Gain from Sale of Equity Method Investment	For financial reporting purposes, income (loss) before income taxes and before the gain from sale of equity method investment for the years ended December 31 include the following components (in thousands): 2015 2014 2013 Domestic $ 1,373 $ (14,223 ) $ (20,466 ) Foreign (1,615 ) (272 ) 1 $ (242 ) $ (14,495 ) $ (20,465 )
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): 2015 2014 2013 Current: Federal $ 144 $ (690 ) $ (1,848 ) State (473 ) 147 284 Foreign 111 124 112 (218 ) (419 ) (1,452 ) Deferred: Federal (274 ) (6 ) 4,491 Foreign 91 — — (183 ) (6 ) 4,491 $ (401 ) $ (425 ) $ 3,039
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): 2015 2014 Deferred tax assets: Research and development tax credit carryforwards $ 12,503 $ 10,756 Stock-based compensation 3,993 3,465 Net operating loss carryforwards 3,393 3,560 Inventory reserves 2,979 3,024 Vacation accrual 1,768 1,821 Investment tax credit carryforwards 1,399 1,446 Alternative minimum tax credit carryforward 340 340 Warranty reserves 202 65 Deferred revenue 192 178 Unrealized loss on investments 149 131 Bad debt reserves 58 59 Accrued severance 35 525 Foreign tax credits — 1,405 Other 700 446 Total deferred tax assets 27,711 27,221 Less: Valuation allowance for deferred tax assets (25,862 ) (25,818 ) Net deferred tax assets 1,849 1,403 Deferred tax liabilities: Depreciation (787 ) (176 ) Prepaid expenses (713 ) (755 ) Patent amortization (334 ) (365 ) Unremitted Vicor Custom Power earnings (55 ) (329 ) Total deferred tax liabilities (1,889 ) (1,625 ) Net deferred tax liabilities $ (40 ) $ (222 )
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): 2015 2014 2013 Balance on January 1 $ 1,254 $ 2,072 $ 1,506 Additions based on tax provisions related to the current year 120 161 566 Reductions for tax positions of prior years — (967 ) — Settlements (480 ) — — Lapse of statute (64 ) (12 ) — Balance on December 31 $ 830 $ 1,254 $ 2,072

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
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 2016 $ 1,314 2017 762 2018 338 2019 213 2020 and thereafter 119

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2015
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) 2015: Net revenues $ 173,064 $ 36,688 $ 17,304 $ — $ (6,862 ) $ 220,194 Income (loss) from operations 21,743 (21,040 ) (290 ) (680 ) — (267 ) Total assets 170,939 15,577 5,369 81,824 (116,164 ) 157,545 Depreciation and amortization 4,538 2,740 442 1,422 — 9,142 2014: 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: 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 (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 Operatio42

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
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 2015: Net revenues $ 64,017 $ 56,119 $ 48,664 $ 51,394 $ 220,194 Gross margin 28,891 26,510 21,286 22,831 99,518 Consolidated net income (loss) 3,442 771 2,609 (1,663 ) 5,159 Net income (loss) attributable to noncontrolling interest 71 (34 ) 106 89 232 Net income (loss) attributable to Vicor Corporation 3,371 805 2,503 (1,752 ) 4,927 Net income (loss) per share attributable to Vicor Corporation: Basic and diluted 0.09 0.02 0.06 (0.05 ) 0.13 First Second Third Fourth Total 2014: 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 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 )

Significant Accounting Polici43

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015USD ($)Customer	Dec. 31, 2014USD ($)Customer	Dec. 31, 2013USD ($)Customer
Revenue, Major Customer [Line Items]
Gross deferred revenue	$ 2,042,000	$ 1,769,000
Gross deferred cost of revenue	$ 882,000	$ 808,000
Revenue recognized under multi-element	3.00%	3.00%	3.00%
Foreign currency losses, net	$ (161,000)	$ (196,000)	$ (94,000)
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 | Customer	1	2
Number of customers | Customer	1	1	2
Cost of advertising	$ 1,762,000	$ 1,832,000	$ 1,884,000
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	16.20%	14.70%
Sales Revenue, Net [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	59.60%	60.50%	59.50%
Sales Revenue, Net [Member] | Hong Kong [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	21.80%	20.20%	16.20%
Sales Revenue, Net [Member] | China [Member] | Geographic Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	12.40%	12.00%	11.30%
Customer One [Member]
Revenue, Major Customer [Line Items]
Percentage of trade account receivable	21.90%	14.90%
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%
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 Polici44

Significant Accounting Policies - Computation Of Basic And Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net income (loss) attributable to Vicor Corporation	$ (1,752)	$ 2,503	$ 805	$ 3,371	$ (3,674)	$ (4,835)	$ (5,378)	$ 4,927	$ (13,887)	$ (23,640)
Denominator:
Denominator for basic net income (loss) per share-weighted average shares								38,754	38,569	39,195
Effect of dilutive securities:
Employee stock options								392
Denominator for diluted net income (loss) per share - adjusted weighted-average shares and assumed conversions								39,146	38,569	39,195
Basic net income (loss) per share								$ 0.13	$ (0.36)	$ (0.60)
Diluted net income (loss) per share								$ 0.13	$ (0.36)	$ (0.60)

Significant Accounting Polici45

Significant Accounting Policies - Computation Of Basic And Diluted Net Income (Loss) Per Share (Parenthetical) (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Options to purchase shares of Common Stock not included in the computation of diluted income (loss) per share	238,792	1,895,675	1,989,248

Stock-Based Compensation and 46

Stock-Based Compensation and Employee Benefit Plans - Additional Information (Detail)	Jun. 21, 2013$ / sharesshares	Jun. 17, 2013Participant$ / sharesshares	May. 14, 2013$ / sharesshares	Nov. 11, 2011shares	Dec. 31, 2014$ / sharesshares	Jun. 30, 2013USD ($)	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares	Dec. 31, 2010shares	Sep. 30, 2010shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of Option							10 years
Eligible participants | Participant		638
Options to purchase shares of Common Stock | shares		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
Stock-based compensation expense							$ 1,782,000	$ 1,634,000	$ 2,450,000
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							$ 854,000	$ 877,000	$ 825,000
Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options | shares							44,500
Time-Based eligible Option exercise price | $ / shares		$ 6.29
Total unrecognized compensation cost							$ 370,000
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 | $ / shares		$ 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 | $ / shares		$ 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 | $ / shares		$ 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 | $ / shares		$ 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 | $ / shares		$ 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 | $ / shares		$ 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 | shares							4,000,000
Non-qualified stock options | shares											1,243,750
Common stock options awarded | shares	70,552		150,000		150,355
Incremental expenses						$ 208,000
Total unrecognized compensation cost							$ 279,000
Immediate expense recognition						190,000
Exercise price of options awarded | $ / shares	$ 5.67		$ 5.35
Stock options, cancelled in period | shares					(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 | shares					1,895,675		1,848,067	1,895,675
Common stock options awarded | shares							194,561
Common stock sales price | $ / shares							$ 12.51
Total unrecognized compensation cost							$ 1,393,000
Stock options, cancelled in period | shares							(117,085)
Vicor options actually vest							88.00%
Annual forfeiture rate							4.25%	8.00%	8.00%
Vicor options actually vest forfeiture								78.00%	78.00%
Share exercisable | shares					306,173		565,861	306,173	54,284
Weighted average exercise prices | $ / shares					$ 6.90		$ 7.24	$ 6.90	$ 9.72
Total Intrinsic value							$ 928,000	$ 751,000	$ 15,000
Options Exercised							805,000	788,000	13,000
Fair value of stock options that vested							$ 1,194,000	$ 1,096,000	$ 489,000
Compensation cost recognized over a weighted-average period							1 year 9 months 18 days
Expected recognized expenses, Year One							$ 726,000
Expected recognized expenses, Year Two							397,000
Expected recognized expenses, Year Three							186,000
Expected recognized expenses, Year Four							71,000
Expected recognized expenses, Year Five							$ 13,000
Weighted-average fair value | $ / shares							$ 6.76	$ 5.50	$ 1.90
Intrinsic value of option exercised							$ 1,269,000
2001 Picor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock reserved for issuance | shares							20,000,000
Non-qualified stock options | shares					0			0
2007 VI Chip Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock reserved for issuance | shares							12,000,000
Non-qualified stock options | shares							0			2,984,250
Common stock options awarded | shares				0
Total unrecognized compensation cost							$ 485,000
Picor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options | shares					9,870,067		9,725,067	9,870,067
Common stock options awarded | shares							82,000
Common stock sales price | $ / shares							$ 1.09
Total unrecognized compensation cost							$ 307,000
Stock options, cancelled in period | shares							(8,000)
Maturity period of US Treasury Bond							7 years
Annual forfeiture rate							2.50%	2.75%	2.75%
Picor options actually vest forfeiture							93.00%
Picor options actually vest								92.00%	92.00%
Share exercisable | shares					6,643,377		8,053,490	6,643,377	5,869,044
Weighted average exercise prices | $ / shares					$ 0.67		$ 0.64	$ 0.67	$ 0.69
Total Intrinsic value							$ 72,000	$ 0	$ 146,000
Options Exercised							14,000		14,000
Fair value of stock options that vested							$ 39,000	$ 0	$ 398,000
Compensation cost recognized over a weighted-average period							2 years 7 months 6 days
Expected recognized expenses, Year One							$ 148,000
Expected recognized expenses, Year Two							86,000
Expected recognized expenses, Year Three							51,000
Expected recognized expenses, Year Four							19,000
Expected recognized expenses, Year Five							$ 3,000
Weighted-average fair value | $ / shares							$ 0.48	$ 0.19	$ 0.31
Intrinsic value of option exercised							$ 3,594,000
Vi Chip Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-qualified stock options | shares					10,715,000		10,097,500	10,715,000
Common stock options awarded | shares							82,500
Common stock sales price | $ / shares							$ 1
Total unrecognized compensation cost							$ 589,000
Stock options, cancelled in period | shares							(699,000)
Maturity period of US Treasury Bond							7 years
Annual forfeiture rate							8.50%	7.75%	7.00%
Chip options actually vest								77.00%	80.00%
Chip options actually vest forfeiture							78.00%
Share exercisable | shares					7,377,950		7,042,600	7,377,950	7,267,600
Weighted average exercise prices | $ / shares					$ 1		$ 1	$ 1	$ 1
Options Exercised							$ 1,000	$ 0	$ 0
Compensation cost recognized over a weighted-average period							3 years
Expected recognized expenses, Year One							$ 192,000
Expected recognized expenses, Year Two							178,000
Expected recognized expenses, Year Three							150,000
Expected recognized expenses, Year Four							$ 69,000
Weighted-average fair value | $ / shares							$ 0.01	$ 0.02	$ 0.29
Intrinsic value of option exercised							$ 0
Stock Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock purchase by non-employees | shares							109,964

Stock-Based Compensation and 47

Stock-Based Compensation and Employee Benefit Plans - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$ 1,782	$ 1,634	$ 2,450
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	230	183	163
Selling, General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	1,246	1,176	1,942
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$ 306	$ 275	$ 345

Stock-Based Compensation and 48

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Vicor [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	2.00%	2.20%	1.20%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	51.00%	52.00%	39.00%
Expected lives (years)	7 years 2 months 12 days	6 years 7 months 6 days	4 years 10 months 24 days
VI Chip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	2.10%	2.30%	1.60%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	37.00%	41.00%	48.00%
Expected lives (years)	6 years 6 months	6 years 6 months	6 years 6 months
Picor [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk-free interest rate	1.90%	2.20%	1.20%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	41.00%	42.00%	49.00%
Expected lives (years)	6 years 6 months	6 years 6 months	6 years 6 months

Stock-Based Compensation and 49

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the 2000 Plan (Detail) - Vicor Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance		1,895,675
Options Outstanding, Granted		194,561
Options Outstanding, Forfeited and expired		(117,085)
Options Outstanding, Exercised		(125,084)
Options Outstanding, Ending balance	1,895,675	1,848,067
Options Outstanding, Exercisable	306,173	565,861	54,284
Options Outstanding, Vested or expected to vest		1,778,075
Weighted Average Exercise Price, Beginning balance		$ 8.07
Weighted Average Exercise Price, Granted		12.51
Weighted Average Exercise Price, Forfeited and expired		9.30
Weighted Average Exercise Price, Exercised		6.44
Weighted Average Exercise Price, Ending balance	$ 8.07	8.57
Weighted Average Exercise Price, Exercisable	$ 6.90	7.24	$ 9.72
Weighted Average Exercise Price, Vested or expected to vest		$ 8.51
Weighted-Average Remaining Contractual Life in Years, Outstanding		7 years 7 months 21 days
Weighted-Average Remaining Contractual Life in Years, Exercisable		7 years 3 months
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest		7 years 7 months 21 days
Aggregate Intrinsic Value, Outstanding		$ 2,637
Aggregate Intrinsic Value, Exercisable		1,269
Aggregate Intrinsic Value, Vested or expected to vest		$ 2,580

Stock-Based Compensation and 50

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the Picor Stock Option Plans (Detail) - Picor Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance		9,870,067
Options Outstanding, Granted		82,000
Options Outstanding, Forfeited and expired		(8,000)
Options Outstanding, Exercised		(219,000)
Options Outstanding, Ending balance	9,870,067	9,725,067
Options Outstanding, Exercisable	6,643,377	8,053,490	5,869,044
Options Outstanding, Vested or expected to vest		9,668,334
Weighted Average Exercise Price, Beginning balance		$ 0.62
Weighted Average Exercise Price, Granted		1.09
Weighted Average Exercise Price, Forfeited and expired		0.75
Weighted Average Exercise Price, Exercised		0.76
Weighted Average Exercise Price, Ending balance	$ 0.62	0.62
Weighted Average Exercise Price, Exercisable	$ 0.67	0.64	$ 0.69
Weighted Average Exercise Price, Vested or expected to vest		$ 0.62
Weighted-Average Remaining Contractual Life in Years, Outstanding		5 years 4 days
Weighted-Average Remaining Contractual Life in Years, Exercisable		4 years 5 months 23 days
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest		4 years 11 months 27 days
Aggregate Intrinsic Value, Outstanding		$ 4,520
Aggregate Intrinsic Value, Exercisable		3,594
Aggregate Intrinsic Value, Vested or expected to vest		$ 4,488

Stock-Based Compensation and 51

Stock-Based Compensation and Employee Benefit Plans - Summary of the Activity under the VI Chip Stock Option Plans (Detail) - Vi Chip Plan [Member] - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Options Outstanding, Beginning balance		10,715,000
Options Outstanding, Granted		82,500
Options Outstanding, Forfeited and expired		(699,000)
Options Outstanding, Exercised		(1,000)
Options Outstanding, Ending balance	10,715,000	10,097,500
Options Outstanding, Exercisable	7,377,950	7,042,600	7,267,600
Options Outstanding, Vested or expected to vest		9,821,129
Weighted Average Exercise Price, Beginning balance		$ 1
Weighted Average Exercise Price, Granted		1
Weighted Average Exercise Price, Forfeited and expired		1
Weighted Average Exercise Price, Exercised		1
Weighted Average Exercise Price, Ending balance	$ 1	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		2 years 10 months 13 days
Weighted-Average Remaining Contractual Life in Years, Exercisable		1 year 9 months
Weighted-Average Remaining Contractual Life in Years, Vested or expected to vest		2 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding		$ 0
Aggregate Intrinsic Value, Exercisable		0
Aggregate Intrinsic Value, Vested or expected to vest		$ 0

Stock-Based Compensation and 52

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, 2015shares
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Granted, shares	82,500
Chief Executive Officer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Granted, shares	5,500,000

Short-Term and Long-Term Inve53

Short-Term and Long-Term Investments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Amortized cost of securities	$ 3,340,000	$ 3,700,000
Minimum period for which failed auction securities been in unrealized loss position	12 months
Estimated Fair Value	$ 2,866,000	3,272,000
Gross unrealized losses	474,000	428,000
Aggregate credit loss	72,000	84,000	$ 395,000	$ 317,000
Failed Auction Security [Member]
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Amortized cost of securities	$ 3,000,000	3,000,000
Period for which failed auction securities been in unrealized loss position	Exceeds 12 months
Estimated Fair Value	$ 2,526,000	2,575,000
Gross unrealized losses	474,000	$ 425,000
Aggregate credit loss	72,000
Aggregate temporary impairment loss	$ 402,000

Short-Term and Long-Term Inve54

Short-Term and Long-Term Investments - Summary of Available-for-Sale Securities (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 3,340,000	$ 3,700,000
Gross Unrealized Gains	0	0
Gross unrealized losses	474,000	428,000
Estimated Fair Value	2,866,000	3,272,000
Failed Auction Security [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	3,000,000	3,000,000
Gross Unrealized Gains	0	0
Gross unrealized losses	474,000	425,000
Estimated Fair Value	2,526,000	2,575,000
Brokered Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	340,000	700,000
Gross Unrealized Gains	0	0
Gross unrealized losses		3,000
Estimated Fair Value	$ 340,000	$ 697,000

Short-Term and Long-Term Inve55

Short-Term and Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Debt Maturities [Abstract]
Due in two to ten years, Cost	$ 340
Due in ten to twenty years, Cost	0
Due in twenty to forty years, Cost	3,000
Cost	3,340	$ 3,700
Due in two to ten years, Estimated Fair Value	340
Due in ten to twenty years, Estimated Fair Value	0
Due in twenty to forty years, Estimated Fair Value	2,526
Estimated Fair Value	$ 2,866	$ 3,272

Short-Term and Long-Term Inve56

Short-Term and Long-Term Investments - Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale Securities, Debt Maturities [Abstract]
Balance at the beginning of the period	$ 84	$ 395	$ 317
Reductions for securities sold during the period		(272)	(7)
Additions (reductions) for the amount related to credit loss for which other-than-temporary impairment was not previously recognized	(12)	(39)	85
Balance at the end of the period	$ 72	$ 84	$ 395

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$ 2,866,000	$ 3,272,000
Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,526,000	2,575,000
Recurring [Member] | Contingent Consideration Obligation [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis	(144,000)
Recurring [Member] | Short-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value		270,000
Recurring [Member] | Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,526,000	2,575,000
Recurring [Member] | Long-Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	340,000	427,000
Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	10,412,000	11,207,000
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	10,412,000	11,207,000
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		270,000
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	340,000	427,000
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Contingent Consideration Obligation [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis	(144,000)
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$ 2,526,000	$ 2,575,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015USD ($)
Fair Value Disclosures [Abstract]
Percent of credit loss	2.40%
Rate of return required	5.00%
Estimated timeframe for auctions of securities minimum	3 years
Estimated timeframe for auctions of securities maximum	5 years
Percentage of liquidity risk premium	5.00%
Increase or decrease in the liquidity risk premium	1.00%
Increase or decrease, respectively, the fair value of the Failed Auction Securities	$ 100,000
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 0

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,866	$ 3,272
Failed Auction Security [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,526
Valuation Technique	Discounted cash flow
Failed Auction Security [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	0.03%
Failed Auction Security [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	93.73%
Failed Auction Security [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 Security [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 Security [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 - Chang

Fair Value Measurements - Change in Estimated Fair Values Calculated for Investment Valued on Recurring Basis Utilizing Level 3 Inputs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Fair Value Disclosures [Abstract]
Balance at the beginning of the period	$ 2,575
Credit gain on available- for- sale security included in Other income (expense), net	12
Loss included in Other comprehensive income (loss)	(61)
Balance at the end of the period	$ 2,526

Fair Value Measurements - Cha61

Fair Value Measurements - Change in Estimated Fair Value Calculated for Liability Valued on Recurring Basis Utilizing Level 3 Inputs (Detail) - Significant Unobservable Inputs (Level 3) [Member] - Contingent Consideration Obligation [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Obligation incurred upon acquisition of noncontrolling interest	$ (144)
Balance at the end of the period	$ (144)

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 16,257	$ 18,252
Work-in-process	2,879	3,339
Finished goods	4,306	4,737
Net balance	$ 23,442	$ 26,328

Property, Plant and Equipment -

Property, Plant and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 9,028,000	$ 9,833,000	$ 10,180,000
Capital expenditure commitments	$ 1,089,000
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 Equipment64

Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Land	$ 2,089	$ 2,089
Buildings and improvements	44,647	43,800
Machinery and equipment	231,305	228,663
Furniture and fixtures	5,652	5,905
Construction in-progress and deposits	3,839	2,568
Property, plant and equipment, gross, total	287,532	283,025
Accumulated depreciation and amortization	(250,082)	(245,638)
Net balance	$ 37,450	$ 37,387

Other Investments - Additional

Other Investments - Additional Information (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)Agreement	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2008USD ($)
Variable Interest Entity [Line Items]
Preferred stock, redemption terms		Redemption was effected through the exchange of a share of preferred stock for (a) the right to receive the preference value in cash upon surrender of the preferred shares and (b) the non-transferable right to receive certain cash payments as additional consideration, after a period of 16 months, associated with (i) the release by Intersil of some or all of the $2,625,000 portion of total consideration held in escrow by Intersil for potential funding of indemnification and related obligations made by GWS and its selling shareholders and (ii) additional consideration of up to $4,000,000, payable in the event Intersil achieved certain revenue goals related to GWS products.
Maximum period to receive non-transferable right as cash		16 months
Consideration held in escrow		$ 2,625,000
Additional consideration payable		$ 4,000,000
Ownership interest in investment		27.00%
Great Wall Semiconductor Corporation (GWS) [Member]
Variable Interest Entity [Line Items]
Gross investment		$ 4,999,719			$ 0
Number of supply agreements with GWS | Agreement		2
Purchase of components under agreement	$ 1,662,000		$ 2,146,000	$ 1,959,000
Payment to obtain rights		$ 500,000
Great Wall Semiconductor Corporation (GWS) [Member] | GWS [Member]
Variable Interest Entity [Line Items]
Company owed GWS		$ 0	$ 170,000
Great Wall Semiconductor Corporation (GWS) [Member] | Licensing Agreement [Member]
Variable Interest Entity [Line Items]
Amortized period of right payments		4 years

Noncontrolling Interest Trans66

Noncontrolling Interest Transactions - Additional Information (Detail) - USD ($)	Dec. 28, 2015	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Noncontrolling interest		$ 1,054,000	$ 2,780,000
Gain on sale of equity		28,000
Contingent consideration	$ 144,000	$ 144,000
Royalty payment description		Through June 30,2021
Reduction of noncontrolling interest		$ 0
Aegis Power Systems Inc [Member]
Noncontrolling Interest [Line Items]
Minority interest percentage by parent	49.00%	49.00%
Minority interest percentage by parent	51.00%
Noncontrolling interest	$ 1,698,000
Deconsolidated cash		$ 2,090,000
Deconsolidated other net assets		$ 1,317,000
Aegis Power Systems Inc [Member] | Other Operating Income (Expense) [Member]
Noncontrolling Interest [Line Items]
Gain on sale of equity	$ 28,000
Mission Power Solutions Inc [Member]
Noncontrolling Interest [Line Items]
Minority interest percentage by parent	18.00%
Noncontrolling interest	$ 216,000

Intangible Assets - Schedule of

Intangible Assets - Schedule of Patent Cost and Other Asset (Detail) - Patents [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Patent costs	$ 2,525	$ 2,721
Accumulated amortization	(1,583)	(1,689)
Finite-lived intangible assets, net	$ 942	$ 1,032

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Patent renewal fees	$ 64,000	$ 25,000
Amortization expense	145,000	$ 170,000	$ 264,000
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Future amortization expense from patent assets held for 2016	133,000
Future amortization expense from patent assets held for 2017	127,000
Future amortization expense from patent assets held for 2018	111,000
Future amortization expense from patent assets held for 2019	105,000
Future amortization expense from patent assets held for 2020	$ 100,000

Severance and Other Charges - A

Severance and Other Charges - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015USD ($)
Restructuring and Related Activities [Abstract]
Severance charges	$ 2,207,000
Other restructuring charges	$ 303,000

Severance and Other Charges - S

Severance and Other Charges - Summary of Activity Related to Accrued Severance Charges by Segment (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Restructuring and Related Activities [Abstract]
Restructuring Reserve, Beginning Balance	$ 1,904
Payments	(1,709)
Restructuring Reserve, Ending Balance	$ 195

Product Warranties - Product Wa

Product Warranties - Product Warranty Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Guarantees [Abstract]
Balance at the beginning of the period	$ 204	$ 283	$ 364
Accruals for warranties for products sold in the period	715	281	327
Fulfillment of warranty obligations	(334)	(350)	(297)
Revisions of estimated obligations		(10)	(111)
Balance at the end of the period	$ 585	$ 204	$ 283

Stockholders' Equity - Addition

Stockholders' Equity - Additional information (Detail) - USD ($)	Apr. 22, 2013	Mar. 07, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	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	Apr. 22, 2013
Common Stock repurchased as per November plan						$ 30,000,000
Stock repurchase program amount available			$ 8,541,000
Cash dividends paid to the Company			250,000	$ 3,738,000	$ 1,569,000
Cash dividends paid to outside shareholders				162,000	531,000
Subsidiaries [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash dividends on subsidiary common stock			$ 250,000	$ 3,900,000	$ 2,100,000
Vicor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock reserved for issuance			14,594,805	14,719,889	14,846,930

Other Income (Expense), Net - C

Other Income (Expense), Net - Components of Other Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income and Expenses [Abstract]
Interest income	$ 47	$ 80	$ 97
Foreign currency losses, net	(161)	(196)	(94)
Gain on disposal of equipment	60	22	26
Credit gains (losses) on available for sale securities	12	311	(78)
Other	67	51	51
Total other income (expense), net	$ 25	$ 268	$ 2

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Federal Statutory Rate on Loss before Income Taxes and before Gain from Sale of Equity Method Investment Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Statutory federal tax rate	(34.00%)	(34.00%)	(34.00%)
State income taxes, net of federal income tax benefit	46.40%	0.80%	1.10%
Tax credits	29.90%	(12.40%)	(8.10%)
Book income attributable to noncontrolling interest	47.00%	(0.60%)	0.40%
Permanent items	21.20%	0.40%	0.60%
Decrease in tax reserves	(248.60%)	(3.70%)	(0.10%)
Foreign rate differential and deferred items	(18.20%)	(0.30%)	(0.20%)
Capital gain on sale to noncontrolling interest	237.80%
Decrease in unremitted Vicor Custom Power earnings	(108.70%)
(Decrease) increase in valuation allowance	(138.40%)	46.90%	53.30%
U.S. manufacturing deduction			1.70%
Other	(0.10%)		0.10%
Effective income tax rate	(165.70%)	(2.90%)	14.80%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 28, 2015	Mar. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Line Items]
Tax benefit recognized			$ 0	$ 0
Recognized tax benefit, voluntary disclosure agreements with several states			555,000
Unremitted earnings reversed			$ 274,000
Benefit for income taxes		$ 552,000
Research tax credit carry forward extension period			2 years
Federal research tax credit recorded							$ 549,000
Unremitted earnings of international subsidiaries			$ 841,000
Unrecognized deferred tax liability			37,000
Gain from equity method investment			5,000,000
Valuation allowance, deferred tax assets			25,862,000	25,818,000
Deferred tax assets valuation allowance increase					$ 10,241,000
Amount generated in cash refund				1,600,000
Increases in equity of realization of deferred tax assets			3,216,000
Accrued interest			830,000	1,254,000	2,072,000			$ 1,506,000
Net interest (benefit) expense			21,000	32,000	$ (28,000)
Potential payment of interest			$ 24,000	$ 181,000
Great Wall Semiconductor Corporation (GWS) [Member]
Income Tax Disclosure [Line Items]
Gain from equity method investment	$ 4,999,719
Gain from equity method investment for income tax purpose	4,999,719
Gain (loss) on transaction for income tax purpose	$ 0
Aegis Power Systems Inc [Member]
Income Tax Disclosure [Line Items]
Sale of ownership interest			49.00%			49.00%
Minimum [Member]
Income Tax Disclosure [Line Items]
Income tax examination period			3 years
Maximum [Member]
Income Tax Disclosure [Line Items]
Income tax examination period			7 years
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Federal net operating loss carryforwards expiry, beginning year			2,033
Certain States [Member]
Income Tax Disclosure [Line Items]
Federal net operating loss carryforwards expiry, beginning year			2,016
Federal net operating loss carryforwards expiry, ending year			2,035

Income Taxes - Schedule of Dome

Income Taxes - Schedule of Domestic and Foreign Components of Income (Loss) Before Income Taxes and before the Gain from Sale of Equity Method Investment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Domestic	$ 1,373	$ (14,223)	$ (20,466)
Foreign	(1,615)	(272)	1
Loss before income taxes	$ (242)	$ (14,495)	$ (20,465)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 144	$ (690)	$ (1,848)
State	(473)	147	284
Foreign	111	124	112
Current, Total	(218)	(419)	(1,452)
Deferred:
Federal	(274)	(6)	4,491
Foreign	91
Deferred Income Tax Expense (Benefit)	(183)	(6)	4,491
Provision (benefit) for income taxes	$ (401)	$ (425)	$ 3,039

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Research and development tax credit carryforwards	$ 12,503,000	$ 10,756,000
Stock-based compensation	3,993,000	3,465,000
Net operating loss carryforwards	3,393,000	3,560,000
Inventory reserves	2,979,000	3,024,000
Vacation accrual	1,768,000	1,821,000
Investment tax credit carryforwards	1,399,000	1,446,000
Alternative minimum tax credit carryforward	340,000	340,000
Warranty reserves	202,000	65,000
Deferred revenue	192,000	178,000
Unrealized loss on investments	149,000	131,000
Bad debt reserves	58,000	59,000
Accrued severance	35,000	525,000
Foreign tax credits		1,405,000
Other	700,000	446,000
Total deferred tax assets	27,711,000	27,221,000
Less: Valuation allowance for deferred tax assets	(25,862,000)	(25,818,000)
Net deferred tax assets	1,849,000	1,403,000
Deferred tax liabilities:
Depreciation	(787,000)	(176,000)
Prepaid expenses	(713,000)	(755,000)
Patent amortization	(334,000)	(365,000)
Unremitted Vicor Custom Power earnings	(55,000)	(329,000)
Total deferred tax liabilities	(1,889,000)	(1,625,000)
Net deferred tax liabilities	$ (40,000)	$ (222,000)

Income Taxes - Schedule of Re79

Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Beginning Balance	$ 1,254	$ 2,072	$ 1,506
Additions based on tax provisions related to the current year	120	161	566
Reductions for tax positions of prior years		(967)
Settlements	(480)
Lapse of statute	(64)	(12)
Unrecognized tax benefits, Ending Balance	$ 830	$ 1,254	$ 2,072

Commitments and Contingencies -

Commitments and Contingencies - Summary of Future Minimum Rental Commitments under Non-Cancelable Operating Leases (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 1,314
2,017	762
2,018	338
2,019	213
2020 and thereafter	$ 119

Commitments and Contingencies81

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 1,902,000	$ 1,824,000	$ 1,820,000

Segment Information - Significa

Segment Information - Significant Segment Financial Data (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net revenues	$ 51,394	$ 48,664	$ 56,119	$ 64,017	$ 60,735	$ 58,402	$ 53,361	$ 53,233	$ 220,194	$ 225,731	$ 199,160
Income (loss) from operations									(267)	(14,763)	(20,467)
Total assets	157,545				155,542				157,545	155,542	165,640
Depreciation and amortization									9,142	9,805	10,008
Operating Segments [Member] | BBU [Member]
Segment Reporting Information [Line Items]
Net revenues									173,064	184,224	163,013
Income (loss) from operations									21,743	15,499	12,062
Total assets	170,939				151,923				170,939	151,923	126,585
Depreciation and amortization									4,538	4,711	6,185
Operating Segments [Member] | VI Chip [Member]
Segment Reporting Information [Line Items]
Net revenues									36,688	34,701	35,333
Income (loss) from operations									(21,040)	(29,015)	(28,204)
Total assets	15,577				17,677				15,577	17,677	21,370
Depreciation and amortization									2,740	3,265	3,232
Operating Segments [Member] | Picor [Member]
Segment Reporting Information [Line Items]
Net revenues									17,304	15,570	10,416
Income (loss) from operations									(290)	(407)	(3,326)
Total assets	5,369				5,691				5,369	5,691	4,308
Depreciation and amortization									442	410	407
Operating Segments [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(680)	(840)	(999)
Total assets	81,824				75,758				81,824	75,758	81,364
Depreciation and amortization									1,422	1,419	184
Eliminations [Member]
Segment Reporting Information [Line Items]
Net revenues									(6,862)	(8,764)	(9,602)
Total assets	$ (116,164)				$ (95,507)				$ (116,164)	$ (95,507)	$ (67,987)

Quarterly Results of Operatio83

Quarterly Results of Operations (Unaudited) - Summary of Unaudited Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 51,394	$ 48,664	$ 56,119	$ 64,017	$ 60,735	$ 58,402	$ 53,361	$ 53,233	$ 220,194	$ 225,731	$ 199,160
Gross margin	22,831	21,286	26,510	28,891	26,116	25,550	22,662	22,792	99,518	97,120	81,479
Consolidated net income (loss)	(1,663)	2,609	771	3,442	(43)	(3,669)	(4,932)	(5,426)	5,159	(14,070)	(23,504)
Net income (loss) attributable to noncontrolling interest	89	106	(34)	71	$ (43)	5	(97)	(48)	232	(183)	136
Net income (loss) attributable to Vicor Corporation	$ (1,752)	$ 2,503	$ 805	$ 3,371		$ (3,674)	$ (4,835)	$ (5,378)	$ 4,927	$ (13,887)	$ (23,640)
Net income (loss) per share attributable to Vicor Corporation:
Basic and diluted	$ (0.05)	$ 0.06	$ 0.02	$ 0.09		$ (0.10)	$ (0.13)	$ (0.14)	$ 0.13	$ (0.36)

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts [Member] - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 183,000	$ 198,000	$ 292,000
Charge to Costs and Expenses	18,000	66,000	255,000
Other Charges, Deductions	(30,000)	(81,000)	(349,000)
Balance at End of Period	$ 171,000	$ 183,000	$ 198,000