Vicor (VICR) 10-Q 3 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 22, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	VICOR CORP
Entity Central Index Key	0000751978
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	VICR
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Document Transition Report	false
Document Quarterly Report	true
Entity File Number	0-18277
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-2742817
Entity Address, Address Line One	25 Frontage Road
Entity Address, City or Town	Andover
Entity Address, Postal Zip Code	01810
City Area Code	978
Local Phone Number	470-2900
Security Exchange Name	NASDAQ
Entity Address, State or Province	MA
Title of 12(b) Security	Common Stock
Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		32,010,275
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		11,758,218

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 178,663	$ 161,742
Short-term investments	50,217	50,166
Accounts receivable, net	51,080	40,999
Inventories, net	63,409	57,269
Other current assets	6,633	6,756
Total current assets	350,002	316,932
Long-term deferred tax assets, net	221	226
Long-term investments, net	2,598	2,517
Property, plant and equipment, net	104,446	74,843
Other assets	1,563	1,721
Total assets	458,830	396,239
Current liabilities:
Accounts payable	18,346	14,121
Accrued compensation and benefits	13,994	14,094
Accrued expenses	3,589	2,624
Short-term lease liabilities	1,625	1,629
Sales allowances	1,661	597
Income taxes payable	10	139
Short-term deferred revenue and customer prepayments	3,390	7,309
Total current liabilities	42,615	40,513
Long-term deferred revenue	493	733
Contingent consideration obligations		227
Long-term income taxes payable	564	643
Long-term lease liabilities	3,504	2,968
Total liabilities	47,176	45,084
Commitments and contingencies (Note 10)
Vicor Corporation stockholders' equity:
Additional paid-in capital	342,014	328,392
Retained earnings	208,753	161,008
Accumulated other comprehensive loss	(1,040)	(204)
Treasury stock at cost: 11,634,806 shares in 2021 and 2020	(138,927)	(138,927)
Total Vicor Corporation stockholders' equity	411,355	350,820
Noncontrolling interest	299	335
Total equity	411,654	351,155
Total liabilities and equity	458,830	396,239
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	$ 437	$ 433

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical)	Sep. 30, 2021Vote$ / sharesshares	Dec. 31, 2020Vote$ / sharesshares
Treasury stock, shares	11,634,806	11,634,806
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	43,635,881	43,204,671
Common Stock, shares outstanding	32,001,075	31,569,865

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net revenues		$ 84,911	$ 78,112	$ 269,083	$ 212,274
Cost of revenues		42,098	44,765	131,699	121,278
Gross margin		42,813	33,347	137,384	90,996
Operating expenses:
Selling, general and administrative		17,322	15,212	50,865	47,036
Research and development		13,519	12,032	39,818	38,197
Total operating expenses		30,841	27,244	90,683	85,233
Income from operations		11,972	6,103	46,701	5,763
Other income (expense), net:
Total unrealized gains on available-for-sale securities, net		37	36	81	81
Less: portion of gains recognized in other comprehensive income		(36)	(35)	(78)	(78)
Net credit gains recognized in earnings		1	1	3	3
Other income (expense), net		393	333	996	712
Total other income (expense), net		394	334	999	715
Income before income taxes		12,366	6,437	47,700	6,478
(Benefit) provision for income taxes		(886)	651	(30)	(249)
Consolidated net income		13,252	5,786	47,730	6,727
Less: Net (loss) income attributable to noncontrolling interest		(7)	1	(15)	10
Net income attributable to Vicor Corporation		$ 13,259	$ 5,785	$ 47,745	$ 6,717
Net income per common share attributable to Vicor Corporation:
Basic		$ 0.30	$ 0.13	$ 1.10	$ 0.16
Diluted		$ 0.29	$ 0.13	$ 1.06	$ 0.15
Shares used to compute net income per common share attributable to Vicor Corporation:
Basic	[1]	43,710	43,164	43,573	41,814
Diluted		45,034	44,743	44,905	43,567
[1]	Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Consolidated net income		$ 13,252	$ 5,786	$ 47,730	$ 6,727
Foreign currency translation (losses) gains, net of tax	[1]	(12)	84	(283)	110
Unrealized (losses) gains on available-for-sale securities, net of tax	[1]	(215)	35	(574)	78
Other comprehensive (loss) income		(227)	119	(857)	188
Consolidated comprehensive income		13,025	5,905	46,873	6,915
Less: Comprehensive (loss) income attributable to noncontrolling interest		(7)	7	(36)	18
Comprehensive income attributable to Vicor Corporation		$ 13,032	$ 5,898	$ 46,909	$ 6,897
[1]	The deferred tax assets associated with foreign currency translation (losses) gains and unrealized (losses) gains on available-for-sale securities are completely offset by a tax valuation allowance as of September 30, 2021 and 2020. Therefore, there is no income tax benefit (provision) recognized for the three and nine months ended September 30, 2021 and 2020.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Recognized income tax benefit (provision)	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Consolidated net income	$ 47,730	$ 6,727
Adjustments to reconcile consolidated net income to net cash provided by (used for) operating activities:
Depreciation and amortization	8,564	8,175
Stock-based compensation expense	5,005	4,286
Decrease in long-term deferred revenue	(240)	(241)
Decrease in contingent consideration obligations	(74)
Gain on disposal of equipment		(9)
Decrease in other assets	56	135
(Decrease) increase in long-term income taxes payable	(79)	8
Deferred income taxes	5	16
Credit gain on available-for-sale securities	(3)	(3)
Provision for doubtful accounts		23
Change in current assets and liabilities, net	(20,737)	(3,742)
Net cash provided by operating activities	40,227	15,375
Investing activities:
Purchases of short-term investments	(50,706)
Sales or maturities of short-term investments	50,000
Additions to property, plant and equipment	(30,942)	(16,837)
Proceeds from sale of equipment		9
Net cash used for investing activities	(31,648)	(16,828)
Financing activities:
Proceeds from employee stock plans	8,621	10,836
Payment of contingent consideration obligations	(153)	(186)
Proceeds from public offering of Common Stock		109,681
Net cash provided by financing activities	8,468	120,331
Effect of foreign exchange rates on cash	(126)	59
Net increase in cash and cash equivalents	16,921	118,937
Cash and cash equivalents at beginning of period	161,742	84,668
Cash and cash equivalents at end of period	$ 178,663	$ 203,605

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Vicor Corporation Stockholders' Equity [Member]	Noncontrolling Interest [Member]	Class B Common Stock [Member]
Beginning Balance at Dec. 31, 2019	$ 205,870	$ 405	$ 201,251	$ 143,098	$ (383)	$ (138,927)	$ 205,562	$ 308	$ 118
Issuance of Common Stock under employee stock plans	10,836	10	10,826				10,836
Issuances of Common Stock in public offering	109,681	18	109,663				109,681
Stock-based compensation expense	4,286		4,286				4,286
Components of comprehensive income, net of tax:
Net income	6,727			6,717			6,717	10
Other comprehensive loss	188				180		180	8
Total comprehensive income (loss)	6,915						6,897	18
Ending Balance at Sep. 30, 2020	337,588	433	326,026	149,815	(203)	(138,927)	337,262	326	118
Beginning Balance at Jun. 30, 2020	326,643	431	320,988	144,030	(316)	(138,927)	326,324	319	118
Issuance of Common Stock under employee stock plans	3,451	2	3,449				3,451
Additional expenses associated with issuance of Common Stock in public offering	(51)		(51)				(51)
Stock-based compensation expense	1,640		1,640				1,640
Components of comprehensive income, net of tax:
Net income	5,786			5,785			5,785	1
Other comprehensive loss	119				113		113	6
Total comprehensive income (loss)	5,905						5,898	7
Ending Balance at Sep. 30, 2020	337,588	433	326,026	149,815	(203)	(138,927)	337,262	326	118
Beginning Balance at Dec. 31, 2020	351,155	433	328,392	161,008	(204)	(138,927)	350,820	335	118
Issuance of Common Stock under employee stock plans	8,621	4	8,617				8,621
Stock-based compensation expense	5,005		5,005				5,005
Components of comprehensive income, net of tax:
Net income	47,730			47,745			47,745	(15)
Other comprehensive loss	(857)				(836)		(836)	(21)
Total comprehensive income (loss)	46,873						46,909	(36)
Ending Balance at Sep. 30, 2021	411,654	437	342,014	208,753	(1,040)	(138,927)	411,355	299	118
Beginning Balance at Jun. 30, 2021	392,892	436	336,278	195,494	(813)	(138,927)	392,586	306	118
Issuance of Common Stock under employee stock plans	3,870	1	3,869				3,870
Stock-based compensation expense	1,867		1,867				1,867
Components of comprehensive income, net of tax:
Net income	13,252			13,259			13,259	(7)
Other comprehensive loss	(227)				(227)		(227)
Total comprehensive income (loss)	13,025						13,032	(7)
Ending Balance at Sep. 30, 2021	$ 411,654	$ 437	$ 342,014	$ 208,753	$ (1,040)	$ (138,927)	$ 411,355	$ 299	$ 118

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements of Vicor Corporation and its consolidated subsidiaries (collectively, the “Company”) have been prepared in accordance with generally accepted accounting principles for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, these interim financial statements do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for any other interim period or the year ending December 31, 2021. The balance sheet at December 31, 2020 presented herein has been derived from the audited financial statements at that date bu t Form 10-K”).

Inventories

Inventories	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	2. 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, handling and customs (e.g., tariff) costs incurred in connection with the sale of products are included in cost of revenues. Inventory that is estimated to be excess, obsolete or unmarketable is written down to net realizable value. The Company’s estimation process for assessing net realizable value is based upon management’s estimate of expected future utility which is derived based on backlog, historical consumption and expected market conditions. If the Company’s estimated demand and/or market expectation were to change or if product sales were to decline, the Company’s estimation process may cause larger inventory reserves to be recorded, resulting in larger charges to cost of revenues. Inventories were as follows (in thousands): September 30, 2021 December 31, 2020 Raw materials $ 46,912 $ 42,556 Work-in-process 11,207 7,424 Finished goods 5,290 7,289 $ 63,409 $ 57,269

Short-Term and Long-Term Invest

Short-Term and Long-Term Investments	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Short-Term and Long-Term Investments	3. Short-Term and Long-Term Investments As of September 30, 2021 and December , the Company held $ ,000 and $ ,000, respectively, of short-term investments, consisting of obligations of the U.S. Treasury, all of which were debt securities with original maturities greater than months but less than year at the time of purchase. As of September 30, 2021 and December 31, 2020, the Company held one auction rate security with a par value of $3,000,000, purchased through and held in custody by a broker-dealer affiliate of Bank of America, N.A., that has experienced failed auctions (the “Failed Auction Security”) since February 2008. The Failed Auction Security held by the Company is Aaa/AA+ rated by 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 September 30, 2021, 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 September 30, 2021. Details of our investments are as follows (in thousands): September 30, 2021 Cash and Short-Term Long-Term Measured at fair value: Available-for-sale debt securities: Money market funds $ 89,254 $ — $ — U.S. Treasury Obligations — 50,217 — Failed Auction Security — — 2,598 Total 89,254 50,217 2,598 Other measurement basis: Cash on hand 89,409 — — Total $ 178,663 $ 50,217 $ 2,598 December 31, 2020 Cash and Short-Term Long-Term Measured at fair value: Available-for-sale debt securities: Money market funds $ 69,493 $ — $ — U.S. Treasury Obligations 19,998 50,166 — Failed Auction Security — — 2,517 Total 89,491 50,166 2,517 Other measurement basis: Cash on hand 72,251 — — Total $ 161,742 $ 50,166 $ 2,517 The following is a summary of the available-for-sale September 30, 2021 Cost Gross Gross Estimated U.S. Treasury Obligations $ 50,216 $ 1 $ — $ 50,217 Failed Auction Security 3,000 — 402 2,598 December 31, 2020 Cost Gross Gross Estimated U.S. Treasury Obligations $ 70,172 $ — $ 8 $ 70,164 Failed Auction Security 3,000 — 483 2,517 As of September 30, 2021, the Failed Auction Security had be e months. The amortized cost and estimated fair value of the available-for-sale Cost Estimated U.S. Treasury Obligations: Maturities greater than three months but less than one year $ 50,216 $ 50,217 $ 50,216 $ 50,217 Cost Estimated Failed Auction Security: Due in twenty to forty years $ 3,000 $ 2,598 Based on the fair value measurements described in Note 4, the fair value of the Failed Auction Security on September 30, 2021, with a par value of $3,000,000, was estimated by the Company to be approximately $2,598,000. The gross unrealized loss of $402,000 on the Failed Auction Security consists of two types of estimated loss: an aggregate credit loss of $30,000 and an aggregate temporary impairment of $372,000. 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. The following table represents a rollforward of the activity related to the credit loss recognized in earnings on the Failed Auction Security for the nine months ended September 30 (in thousands): 2021 2020 Balance at the beginning of the period $ 33 $ 37 Reductions in the amount related to credit gain for which other-than- temporary impairment was not previously recognized (3 ) (3 ) Balance at the end of the period $ 30 $ 34 At this time, the Company has no intent to sell the impaired Failed Auction Security and does not believe it is more likely than not the Company will be required to sell this 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 Condensed Consolidated Statements of Operations, and any such impairment adjustments may be material. Based on the Company’s ability to access cash and cash equivalents, its short-term investments 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	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. 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 September 30, 2021 (in thousands): Using Quoted Prices Significant Significant (Level Total Fair Cash equivalents: Money market funds $ 89,254 $ — $ — $ 89,254 Short-term investments: U.S. Treasury Obligations 50,217 — — 50,217 Long-term investment: Failed Auction Security — — 2,598 2,598 Assets and liabilities measured at fair value on a recurring basis included the following as of December 31, 2020 (in thousands): Using Significant Quoted Prices Other Significant Total Fair Cash equivalents: Money market funds $ 69,493 $ — $ — $ 69,493 U.S. Treasury Obligations 19,998 — — 19,998 Short-term investments: U.S. Treasury Obligations 50,166 — — 50,166 Long-term investment: Failed Auction Security — — 2,517 2,517 Liabilities: Contingent consideration obligations — — (227 ) (227 ) As of September 30, 2021, 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 September 30, 2021. The major assumptions used in preparing the DCF model were similar to those described in Note 5 - Fair Value Measurements in the Notes to the Consolidated Financial Statements contained in the Company’s 2020 Form 10-K. Quantitative information about Level 3 fair value measurements as of September 30, 2021 is as follows (dollars in thousands): Fair Value Valuation Technique Unobservable Input Weighted Failed Auction Security $ 2,598 Discounted cash flow Cumulative probability of earning the maximum rate until maturity 0.15% Cumulative probability of principal return prior to maturity 94.71% Cumulative probability of default 5.14% 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 nine months ended September 30, 2021 was as follows (in thousands): Balance at the beginning of the period $ 2,517 Credit gain on available-for-sale security included in Other income (expense), net 3 Gain included in Other comprehensive income 78 Balance at the end of the period $ 2,598 There were no transfers between Level 1 and Level 2 of the fair value hierarchy during the nine months ended September 30, 2021.

Revenues

Revenues	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenues	5. Revenues The following tables present the Company’s net revenues disaggr e Three Months Ended September 30, 2021 Brick Products Advanced Products Total United States $ 19,741 $ 12,178 $ 31,919 Europe 6,185 1,324 7,509 Asia Pacific 14,936 29,934 44,870 All other 582 31 613 $ 41,444 $ 43,467 $ 84,911 Nine Months Ended September 30, 2021 Brick Products Advanced Products Total United States $ 58,032 $ 35,083 $ 93,115 Europe 24,605 3,604 28,209 Asia Pacific 66,309 79,926 146,235 All other 1,309 215 1,524 $ 150,255 $ 118,828 $ 269,083 Three Months Ended September 30, 2020 Brick Products Advanced Products Total United States $ 16,905 $ 4,391 $ 21,296 Europe 4,456 2,050 6,506 Asia Pacific 25,878 23,926 49,804 All other 454 52 506 $ 47,693 $ 30,419 $ 78,112 Nine Months Ended September 30, 2020 Brick Products Advanced Products Total United States $ 57,880 $ 17,205 $ 75,085 Europe 18,451 5,218 23,669 Asia Pacific 60,917 50,076 110,993 All other 2,390 137 2,527 $ 139,638 $ 72,636 $ 212,274 The following tables present the Company’s net revenues disaggregated by the category of revenue, by product line (in thousands): Three Months Ended September 30, 2021 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 29,801 $ 36,066 $ 65,867 Stocking distributors, net of sales allowances 11,405 2,075 13,480 Non-recurring engineering 238 3,846 4,084 Royalties — 1,462 1,462 Other — 18 18 $ 41,444 $ 43,467 $ 84,911 Nine Months Ended September 30, 2021 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 111,223 $ 97,767 $ 208,990 Stocking distributors, net of sales allowances 38,586 10,847 49,433 Non-recurring engineering 446 8,643 9,089 Royalties — 1,518 1,518 Other — 53 53 $ 150,255 $ 118,828 $ 269,083 Three Months Ended September 30, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 40,916 $ 27,422 $ 68,338 Stocking distributors, net of sales allowances 6,661 1,463 8,124 Non-recurring engineering 116 1,499 1,615 Royalties — 17 17 Other — 18 18 $ 47,693 $ 30,419 $ 78,112 Nine Months Ended September 30, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 116,127 $ 62,233 $ 178,360 Stocking distributors, net of sales allowances 23,097 6,101 29,198 Non-recurring engineering 414 4,231 4,645 Royalties — 17 17 Other — 54 54 $ 139,638 $ 72,636 $ 212,274 The following table prese n September 30, December 31, 2020 Change Accounts receivable $ 51,080 $ 40,999 $ 10,081 Short-term deferred revenue and customer prepayments (3,390 ) (7,309 ) 3,919 Long-term deferred revenue (493 ) (733 ) 240 Deferred expenses 848 1,650 (802 ) Sales allowances (1,661 ) (597 ) (1,064 ) The increase in accounts receivable was primarily due to an increase in net revenues of approximately $9,224,000 in August through September 2021 compared to November through December 2020. The decrease in short-term deferred revenue and customer prepayments was primarily due to the recognition of approximately $2,410,000 of the associated revenue during the second quarter of 2021. The increase in sales allowances was primarily due to the increase in the year-to-date Deferred expenses are included in Other current assets in the accompanying Condensed Consolidated Balance Sheets. The Company records deferred revenue, which represents a contract liability, when cash payments are received or due in advance of performance under a contract with a customer. The Company recognized revenue of approximately $874,000 and $3,955,000 for the three and nine months ended September 30, 2021, respectively, and $388,000 and $1,736,000 for the three and nine months ended September 30, 2020, respectively, that was included in deferred revenue at the beginning of each respective period.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	6. Stock-Based Compensation The Company uses the Black-Scholes option pricing model to calculate the fair value of stock option awards, whether they possess time-based vesting provisions or performance-based vesting provisions, and awards granted under the Vicor Corporation 2017 Employee Stock Purchase Plan (“ESPP”), as of their grant date. Stock-based compensation expense was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Cost of revenues $ 259 $ 296 $ 739 $ 692 Selling, general and administrative 1,033 846 2,665 2,313 Research and development 575 498 1,601 1,281 Total stock-based compensation $ 1,867 $ 1,640 $ 5,005 $ 4,286 Compensation expense by type of award was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Stock options $ 1,661 $ 1,420 $ 4,328 $ 3,663 ESPP 206 220 677 623 Total stock-based compensation $ 1,867 $ 1,640 $ 5,005 $ 4,286 The increase in stock option compensation expense for the three and nine months ended September 30, 2021 compared to the three and nine months ended September 30, 2020, was primarily due to an increase in the number of stock options granted and higher stock-based compensation expense associated with June 2021 stock opti o

Rental Income

Rental Income	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Rental Income	7. Rental Income Income, net under the Company’s operating lease agreement, for its owned facility leased to a third party in California, was approximately $ and $ for the three and nine months ended September 30, 2021 and 2020, respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The (benefit) provision for income taxes is based on the estimated annual effective tax rate for the year, which includes estimated federal, state and foreign income taxes on the Company’s projected pre-tax The (benefit) provision for income taxes and the effective income tax rates were as follows (dollars in thousands): Three Months Ende d Nine Months Ended September 30, September 30, 2021 2020 2021 2020 (Benefit) provision for income taxes $ (886) $ 651 $ (30) $ (249) Effective income tax rate (7.2)% 10.1% (0.1)% (3.8)% The effective tax rates were lower than the statutory tax r a As of September 30, 2021, the Company had a valuation allowance of approximately $37,856,000 against all net domestic 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. While recent positive operating results, as a result of increases in bookings, caused the Company to be in a cumulative income position as of September 30, 2021, the Company faces uncertainties in forecasting its operating results due to continued negative impacts on the Company’s supply chain, certain process issues with the production of Advanced Products and unpredictability in certain markets. This operating uncertainty also makes it difficult to predict the availability and utilization of tax benefits over the next several years. As a result, management has concluded, at this time, it is more likely than not the Company’s net domestic deferred tax assets will not be realized, and a full valuation allowance against all net domestic deferred tax assets was still warranted as of September 30, 2021. 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 the positive quarterly earnings and increases in bookings continue, and the Company’s concerns about industry uncertainty and world events, including continued negative impacts on the Company’s supply chain, and process issues with the production of Advanced Products are resolved, and the amount of tax benefits the Company is able to utilize to the point that the Company believes future taxable income can be more reliably forecasted, the Company may release all or a portion of the valuation allowance in the near-term. However, the valuation allowance against certain state tax credits will likely never be released due to uncertainty on the utilization of these credits. 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. The Company was informed in September 2021 by the Internal Revenue Service of their intention to examine the Company’s 2019 Federal income tax return. There are no other audits or examinations in process in any other jurisdiction.

Net Income per Share

Net Income per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income per Share	9. Net Income per Share The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Numerator: Net income attributable to Vicor Corporation $ 13,259 $ 5,785 $ 47,745 $ 6,717 Denominator: Denominator for basic net income per share-weighted average shares (1) 43,710 43,164 43,573 41,814 Effect of dilutive securities: Employee stock options (2) 1,324 1,579 1,332 1,753 Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions 45,034 44,743 44,905 43,567 Basic net income per share $ 0.30 $ 0.13 $ 1.10 $ 0.16 Diluted net income per share $ 0.29 $ 0.13 $ 1.06 $ 0.15 (1) Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding. (2) Options to purchase 76,114 and 134,822 shares of Common Stock for the three and nine months ended September 30, 2021, respectively, and options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, were not included in the calculations of net income per share as the effect would have been antidilutive.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies At September 30, 2021, the Company had approximately $22,046,000 of capital expenditure commitments, principally for manufacturing equipment, and approximately $6,607,000 of capital expenditure items which had been received and included in Property, plant and equipment in the accompanying Condensed Consolidated Balance Sheets, but not yet paid for. In addition to these commitments, the Company has, in the aggregate, approximately $20,000,000 of remaining budgeted capital expenditures expected to be incurred through the first half of 2022 associated with the construction of a sq. ft. addition to the Company’s existing manufacturing facility and the installation of new production equipment. The Company is the defendant in a patent infringement lawsuit originally filed on January 28, 2011 by SynQor, Inc. (“SynQor”) in the U.S. District Court for the Eastern District of Texas (the “Texas Action”). The complaint, as amended, alleges that the Company’s products, including but not limited to, unregulated bus converters used in intermediate bus architecture power supply systems, infringe SynQor’s U.S. patent numbers 7,072,190, 7,272,021, 7,564,702, and 8,023,290 (“the ‘190 patent”, “the ‘021 patent”, “the ‘702 patent”, and “the ‘290 patent”, respectively). SynQor’s complaint sought an injunction against further infringement and an award of unspecified compensatory and enhanced damages, interest, costs and attorney fees. The Company has denied that its products infringe any of the SynQor patents, and has asserted that the SynQor patents are invalid and/or unenforceable. The Company has also asserted counterclaims seeking damages from SynQor for deceptive trade practices and tortious interference with prospective economic advantage arising from SynQor’s attempted enforcement of its patents against the Company. The Texas Action is currently stayed by the District Court pending completion of certain inter partes reexamination (“IPRx”) proceedings initiated by the Company at the United States Patent and Trademark Office (“USPTO”) (including any appeals to the United States Court of Appeals for the Federal Circuit (the “Federal Circuit”)). In these IPRx proceedings, the Company challenged the validity of the SynQor patent claims asserted in the Texas Action. On March 17, 2021, SynQor filed a motion to lift the stay in t The current status of the IPRx proceedings is as follows: • ‘190 patent: Certain claims of the ‘190 patent were found unpatentable by the Federal Circuit in a decision issued on March 13, 2015. The court remanded the remaining claims to the USPTO for further consideration. On February 20, 2019, the Patent Trial and Appeal Board (“PTAB”) of the USPTO issued a decision finding that all of the remaining challenged claims were unpatentable. SynQor appealed that decision. On February 22, 2021, the Federal Circuit issued a decision in that appeal. In a 2-1 • ‘021 patent: On August 30, 2017, the Federal Circuit issued a final decision finding all of the asserted claims of the ‘021 patent unpatentable. • ‘702 patent: On August 30, 2017, the Federal Circuit issued a final decision finding all of the asserted claims of the ‘702 patent to be patentable. • ‘290 patent: On June 16, 2021, the PTAB issued a decision finding all of the claims of the ‘290 patent unpatentable. SynQor has filed an appeal of that decision to the Federal Circuit, where it remains pending. On January 23, 2018, the 20-year 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. The Company believes SynQor’s claims lack merit and, therefore, it 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.

Impact of Recently Issued Accou

Impact of Recently Issued Accounting Standards	9 Months Ended
	Sep. 30, 2021
Accounting Changes and Error Corrections [Abstract]
Impact of Recently Issued Accounting Standards	11. Impact of Recently Issued Accounting Standards In December 2019, the Financial Accounting Standards Board (“FASB”) issued guidance designed to simplify the accounting for income taxes by eliminating certain exceptions to the general principles in Topic 740, Income Taxes, and also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. This new guidance was effective for the Company for its fiscal year beginning after December 15, 2020, with early adoption permitted. The Company adopted the new guidance as of January 1, 2021. The adoption did not have a material impact on the Company’s consolidated financial statements and disclosures. Other new pronouncements issued but not effective until after September 30, 2021 are not expected to have a material impact on the Company’s consolidated financial statements.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories were as follows (in thousands): September 30, 2021 December 31, 2020 Raw materials $ 46,912 $ 42,556 Work-in-process 11,207 7,424 Finished goods 5,290 7,289 $ 63,409 $ 57,269

Short-Term and Long-Term Inve_2

Short-Term and Long-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Summary of Investment	Details of our investments are as follows (in thousands): September 30, 2021 Cash and Short-Term Long-Term Measured at fair value: Available-for-sale debt securities: Money market funds $ 89,254 $ — $ — U.S. Treasury Obligations — 50,217 — Failed Auction Security — — 2,598 Total 89,254 50,217 2,598 Other measurement basis: Cash on hand 89,409 — — Total $ 178,663 $ 50,217 $ 2,598 December 31, 2020 Cash and Short-Term Long-Term Measured at fair value: Available-for-sale debt securities: Money market funds $ 69,493 $ — $ — U.S. Treasury Obligations 19,998 50,166 — Failed Auction Security — — 2,517 Total 89,491 50,166 2,517 Other measurement basis: Cash on hand 72,251 — — Total $ 161,742 $ 50,166 $ 2,517
Summary of Available-for-Sale Securities	The following is a summary of the available-for-sale September 30, 2021 Cost Gross Gross Estimated U.S. Treasury Obligations $ 50,216 $ 1 $ — $ 50,217 Failed Auction Security 3,000 — 402 2,598 December 31, 2020 Cost Gross Gross Estimated U.S. Treasury Obligations $ 70,172 $ — $ 8 $ 70,164 Failed Auction Security 3,000 — 483 2,517
Cost and Estimated Fair Value of Failed Auction Security by Contractual Maturities	The amortized cost and estimated fair value of the available-for-sale Cost Estimated U.S. Treasury Obligations: Maturities greater than three months but less than one year $ 50,216 $ 50,217 $ 50,216 $ 50,217 Cost Estimated Failed Auction Security: Due in twenty to forty years $ 3,000 $ 2,598
Rollforward of Credit (Gain) Loss Recognized in Earnings on Failed Auction Security	The following table represents a rollforward of the activity related to the credit loss recognized in earnings on the Failed Auction Security for the nine months ended September 30 (in thousands): 2021 2020 Balance at the beginning of the period $ 33 $ 37 Reductions in the amount related to credit gain for which other-than- temporary impairment was not previously recognized (3 ) (3 ) Balance at the end of the period $ 30 $ 34

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 (in thousands): Using Quoted Prices Significant Significant (Level Total Fair Cash equivalents: Money market funds $ 89,254 $ — $ — $ 89,254 Short-term investments: U.S. Treasury Obligations 50,217 — — 50,217 Long-term investment: Failed Auction Security — — 2,598 2,598 Assets and liabilities measured at fair value on a recurring basis included the following as of December 31, 2020 (in thousands): Using Significant Quoted Prices Other Significant Total Fair Cash equivalents: Money market funds $ 69,493 $ — $ — $ 69,493 U.S. Treasury Obligations 19,998 — — 19,998 Short-term investments: U.S. Treasury Obligations 50,166 — — 50,166 Long-term investment: Failed Auction Security — — 2,517 2,517 Liabilities: Contingent consideration obligations — — (227 ) (227 )
Quantitative Information about Level 3 Fair Value Measurements	Quantitative information about Level 3 fair value measurements as of September 30, 2021 is as follows (dollars in thousands): Fair Value Valuation Technique Unobservable Input Weighted Failed Auction Security $ 2,598 Discounted cash flow Cumulative probability of earning the maximum rate until maturity 0.15% Cumulative probability of principal return prior to maturity 94.71% Cumulative probability of default 5.14% 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 nine months ended September 30, 2021 was as follows (in thousands): Balance at the beginning of the period $ 2,517 Credit gain on available-for-sale security included in Other income (expense), net 3 Gain included in Other comprehensive income 78 Balance at the end of the period $ 2,598

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2021
Summary of Net Revenues Based On Geography Location	The following tables present the Company’s net revenues disaggr e Three Months Ended September 30, 2021 Brick Products Advanced Products Total United States $ 19,741 $ 12,178 $ 31,919 Europe 6,185 1,324 7,509 Asia Pacific 14,936 29,934 44,870 All other 582 31 613 $ 41,444 $ 43,467 $ 84,911 Nine Months Ended September 30, 2021 Brick Products Advanced Products Total United States $ 58,032 $ 35,083 $ 93,115 Europe 24,605 3,604 28,209 Asia Pacific 66,309 79,926 146,235 All other 1,309 215 1,524 $ 150,255 $ 118,828 $ 269,083 Three Months Ended September 30, 2020 Brick Products Advanced Products Total United States $ 16,905 $ 4,391 $ 21,296 Europe 4,456 2,050 6,506 Asia Pacific 25,878 23,926 49,804 All other 454 52 506 $ 47,693 $ 30,419 $ 78,112 Nine Months Ended September 30, 2020 Brick Products Advanced Products Total United States $ 57,880 $ 17,205 $ 75,085 Europe 18,451 5,218 23,669 Asia Pacific 60,917 50,076 110,993 All other 2,390 137 2,527 $ 139,638 $ 72,636 $ 212,274
Summary of Net Revenues Disaggregated by Geography	The following tables present the Company’s net revenues disaggregated by the category of revenue, by product line (in thousands): Three Months Ended September 30, 2021 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 29,801 $ 36,066 $ 65,867 Stocking distributors, net of sales allowances 11,405 2,075 13,480 Non-recurring engineering 238 3,846 4,084 Royalties — 1,462 1,462 Other — 18 18 $ 41,444 $ 43,467 $ 84,911 Nine Months Ended September 30, 2021 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 111,223 $ 97,767 $ 208,990 Stocking distributors, net of sales allowances 38,586 10,847 49,433 Non-recurring engineering 446 8,643 9,089 Royalties — 1,518 1,518 Other — 53 53 $ 150,255 $ 118,828 $ 269,083 Three Months Ended September 30, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 40,916 $ 27,422 $ 68,338 Stocking distributors, net of sales allowances 6,661 1,463 8,124 Non-recurring engineering 116 1,499 1,615 Royalties — 17 17 Other — 18 18 $ 47,693 $ 30,419 $ 78,112 Nine Months Ended September 30, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking distributors $ 116,127 $ 62,233 $ 178,360 Stocking distributors, net of sales allowances 23,097 6,101 29,198 Non-recurring engineering 414 4,231 4,645 Royalties — 17 17 Other — 54 54 $ 139,638 $ 72,636 $ 212,274
Summary of Changes in Contract Assets And Liabilities	The following table prese n September 30, December 31, 2020 Change Accounts receivable $ 51,080 $ 40,999 $ 10,081 Short-term deferred revenue and customer prepayments (3,390 ) (7,309 ) 3,919 Long-term deferred revenue (493 ) (733 ) 240 Deferred expenses 848 1,650 (802 ) Sales allowances (1,661 ) (597 ) (1,064 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Stock-Based Compensation Expense	Stock-based compensation expense was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Cost of revenues $ 259 $ 296 $ 739 $ 692 Selling, general and administrative 1,033 846 2,665 2,313 Research and development 575 498 1,601 1,281 Total stock-based compensation $ 1,867 $ 1,640 $ 5,005 $ 4,286
Summary of Compensation Expense by Type of Award	Compensation expense by type of award was as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Stock options $ 1,661 $ 1,420 $ 4,328 $ 3,663 ESPP 206 220 677 623 Total stock-based compensation $ 1,867 $ 1,640 $ 5,005 $ 4,286

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Provision For Income Taxes And Effective Income Tax Rate Table Text Block [Table Text Block]	The (benefit) provision for income taxes and the effective income tax rates were as follows (dollars in thousands): Three Months Ende d Nine Months Ended September 30, September 30, 2021 2020 2021 2020 (Benefit) provision for income taxes $ (886) $ 651 $ (30) $ (249) Effective income tax rate (7.2)% 10.1% (0.1)% (3.8)%

Net Income per Share (Tables)

Net Income per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income Per Share	The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, September 30, 2021 2020 2021 2020 Numerator: Net income attributable to Vicor Corporation $ 13,259 $ 5,785 $ 47,745 $ 6,717 Denominator: Denominator for basic net income per share-weighted average shares (1) 43,710 43,164 43,573 41,814 Effect of dilutive securities: Employee stock options (2) 1,324 1,579 1,332 1,753 Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions 45,034 44,743 44,905 43,567 Basic net income per share $ 0.30 $ 0.13 $ 1.10 $ 0.16 Diluted net income per share $ 0.29 $ 0.13 $ 1.06 $ 0.15 (1) Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding. (2) Options to purchase 76,114 and 134,822 shares of Common Stock for the three and nine months ended September 30, 2021, respectively, and options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, were not included in the calculations of net income per share as the effect would have been antidilutive.

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 46,912	$ 42,556
Work-in-process	11,207	7,424
Finished goods	5,290	7,289
Net balance	$ 63,409	$ 57,269

Short-Term and Long-Term Inve_3

Short-Term and Long-Term Investments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Short Term Investments	$ 50,217,000	$ 50,166,000
Minimum period for which failed auction securities been in unrealized loss position	12 months
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	$ 2,598,000	2,517,000
Gross Unrealized Losses	402,000	483,000
Aggregate credit loss	30,000	$ 33,000	$ 34,000	$ 37,000
Aggregate temporary impairment loss	$ 372,000

Short-Term and Long-Term Inve_4

Short-Term and Long-Term Investments - Summary of Investment (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	$ 178,663	$ 161,742
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	50,217	50,166
Other Long-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	2,598	2,517
Estimate of Fair Value Measurement [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	89,254	89,491
Estimate of Fair Value Measurement [Member] | Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	50,217	50,166
Estimate of Fair Value Measurement [Member] | Other Long-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	2,598	2,517
Estimate of Fair Value Measurement [Member] | Auction Rate Securities [Member] | Other Long-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	2,598	2,517
Estimate of Fair Value Measurement [Member] | Money Market Funds [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	89,254	69,493
Estimate of Fair Value Measurement [Member] | US Treasury Obligations [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale		19,998
Estimate of Fair Value Measurement [Member] | US Treasury Obligations [Member] | Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	50,217	50,166
Portion at Other than Fair Value Measurement [Member] | Cash [Member] | Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale	$ 89,409	$ 72,251

Short-Term and Long-Term Inve_5

Short-Term and Long-Term Investments - Summary of Available-for-Sale Securities (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
US Treasury Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	$ 50,216,000	$ 70,172,000
Gross Unrealized Gains	1,000
Gross Unrealized Losses		8,000
Estimated Fair Value	50,217,000	70,164,000
Failed Auction Security [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	3,000,000	3,000,000
Gross Unrealized Losses	402,000	483,000
Estimated Fair Value	$ 2,598,000	$ 2,517,000

Short-Term and Long-Term Inve_6

Short-Term and Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 50,216
Available For Sale Debt Securities Estimated Fair Value	50,217
Failed Auction Security [Member]
Schedule of Available-for-sale Securities [Line Items]
Due in twenty to forty years, Cost	3,000
Due in twenty to forty years, Estimated Fair Value	2,598
US Treasury Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturities greater than three months but less than one year, Cost	50,216
Maturities greater than three months but less than one year, Estimated Fair Value	$ 50,217

Short-Term and Long-Term Inve_7

Short-Term and Long-Term Investments - Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities (Detail) - Failed Auction Security [Member] - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Balance at the beginning of the period	$ 33,000	$ 37,000
Reductions in the amount related to credit gain for which other-than- temporary impairment was not previously recognized	(3,000)	(3,000)
Balance at the end of the period	$ 30,000	$ 34,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Contingent Consideration Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis		$ (227,000)
Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$ 2,598,000	2,517,000
Failed Auction Security [Member] | Other Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,598,000	2,517,000
US Treasury Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	50,217,000	19,998,000
Estimated Fair Value	50,217,000	70,164,000
US Treasury Obligations [Member] | Short-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value		50,166,000
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	89,254,000	69,493,000
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | US Treasury Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	50,217,000	19,998,000
Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | US Treasury Obligations [Member] | Short-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value		50,166,000
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	89,254,000	69,493,000
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Contingent Consideration Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis		(227,000)
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Failed Auction Security [Member] | Other Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	$ 2,598,000	$ 2,517,000

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Detail) - Failed Auction Security [Member] - Significant Unobservable Inputs (Level 3) [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,598
Cumulative Probability of Earning Maximum Rate Until Maturity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted cash flow
Unobservable Input	Cumulative probability of earning the maximum rate until maturity
Weighted Average Interest Rate	0.15%
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	94.71%
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	5.14%
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%
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	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value Disclosures [Abstract]
Balance at the beginning of the period	$ 2,517
Credit gain on available-for-sale security included in Other income (expense), net	3
Gain included in Other comprehensive income	78
Balance at the end of the period	$ 2,598

Revenues - Summary of Net Reven

Revenues - Summary of Net Revenues Disaggregated by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 84,911	$ 78,112	$ 269,083	$ 212,274
Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	41,444	47,693	150,255	139,638
Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	43,467	30,419	118,828	72,636
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	31,919	21,296	93,115	75,085
United States [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	19,741	16,905	58,032	57,880
United States [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	12,178	4,391	35,083	17,205
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	7,509	6,506	28,209	23,669
Europe [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	6,185	4,456	24,605	18,451
Europe [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,324	2,050	3,604	5,218
Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	44,870	49,804	146,235	110,993
Asia Pacific [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	14,936	25,878	66,309	60,917
Asia Pacific [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	29,934	23,926	79,926	50,076
All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	613	506	1,524	2,527
All Other [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	582	454	1,309	2,390
All Other [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 31	$ 52	$ 215	$ 137

Revenues - Summary of Net Rev_2

Revenues - Summary of Net Revenues Disaggregated by Category (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 84,911	$ 78,112	$ 269,083	$ 212,274
Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	41,444	47,693	150,255	139,638
Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	43,467	30,419	118,828	72,636
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member]
Disaggregation of Revenue [Line Items]
Revenue	65,867	68,338	208,990	178,360
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	29,801	40,916	111,223	116,127
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	36,066	27,422	97,767	62,233
Stocking Distributors, Net of Sales Allowances [Member]
Disaggregation of Revenue [Line Items]
Revenue	13,480	8,124	49,433	29,198
Stocking Distributors, Net of Sales Allowances [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	11,405	6,661	38,586	23,097
Stocking Distributors, Net of Sales Allowances [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	2,075	1,463	10,847	6,101
Non-recurring Engineering [Member]
Disaggregation of Revenue [Line Items]
Revenue	4,084	1,615	9,089	4,645
Non-recurring Engineering [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	238	116	446	414
Non-recurring Engineering [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	3,846	1,499	8,643	4,231
Royalties [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,462	17	1,518	17
Royalties [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,462	17	1,518	17
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	18	18	53	54
Other [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 18	$ 18	$ 53	$ 54

Revenues - Summary of Changes i

Revenues - Summary of Changes in Certain Contract Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 51,080	$ 40,999
Short-term deferred revenue and customer prepayments	(3,390)	(7,309)
Long-term deferred revenue	(493)	(733)
Deferred expenses	848	1,650
Sales allowances	(1,661)	$ (597)
Accounting Standards Update 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Accounts receivable	10,081
Short-term deferred revenue and customer prepayments	3,919
Long-term deferred revenue	240
Deferred expenses	(802)
Sales allowances	$ (1,064)

Revenues - Additional Informati

Revenues - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Increase in net revenues				$ 9,224,000
Deferred Revenue, Revenue Recognized	$ 874,000		$ 388,000	$ 3,955,000	$ 1,736,000
Decrease in short-term deferred revenue and customer prepayments		$ 2,410,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,867	$ 1,640	$ 5,005	$ 4,286
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	259	296	739	692
Selling, General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,033	846	2,665	2,313
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 575	$ 498	$ 1,601	$ 1,281

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Compensation Expense by Type of Award (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,867	$ 1,640	$ 5,005	$ 4,286
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,661	1,420	4,328	3,663
ESPP [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 206	$ 220	$ 677	$ 623

Rental Income - Additional info

Rental Income - Additional information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Lease income	$ 198,000	$ 594,000	$ 198,000	$ 594,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	Sep. 30, 2021USD ($)
Income Tax Disclosure [Line Items]
Valuation allowance, deferred tax assets	$ 37,856,000

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes and Effective Income Tax Rates (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ (886)	$ 651	$ (30)	$ (249)
Effective income tax rate	(7.20%)	10.10%	(0.10%)	(3.80%)

Net Income per Share - Computat

Net Income per Share - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss) attributable to Vicor Corporation		$ 13,259	$ 5,785	$ 47,745	$ 6,717
Denominator:
Denominator for basic net income per share-weighted average shares	[1]	43,710	43,164	43,573	41,814
Effect of dilutive securities:
Employee stock options	[2]	1,324	1,579	1,332	1,753
Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions		45,034	44,743	44,905	43,567
Basic net income (loss) per share		$ 0.30	$ 0.13	$ 1.10	$ 0.16
Diluted net income (loss) per share		$ 0.29	$ 0.13	$ 1.06	$ 0.15
[1]	Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding.
[2]	Options to purchase 76,114 and 134,822 shares of Common Stock for the three and nine months ended September 30, 2021, respectively, and options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, were not included in the calculations of net income per share as the effect would have been antidilutive.

Net Income per Share - Comput_2

Net Income per Share - Computation of Basic and Diluted Net Income Per Share (Parenthetical) (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Options to purchase shares of Common Stock not included in the computation of diluted income per share	76,114	265,725	134,822	130,027

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2021USD ($)ft²
Commitments and Contingencies Disclosure [Abstract]
Capital expenditure commitments	$ 22,046,000
Budgeted capital expenditures	$ 20,000,000
Area of Land | ft²	90,000
Capital expenditures incurred but not yet paid	$ 6,607,000