Vicor (VICR) 10-Q 30 Oct 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 26, 2020
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
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 Quarterly Report	true
Document Transition Report	false
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		31,517,044
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, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 203,605	$ 84,668
Accounts receivable, less allowance of $82 in 2020 and $59 in 2019	41,136	38,115
Inventories, net	58,169	49,187
Other current assets	6,872	7,096
Total current assets	309,782	179,066
Long-term deferred tax assets, net	189	205
Long-term investment, net	2,591	2,510
Property, plant and equipment, net	65,780	56,952
Other assets	1,777	1,994
Total assets	380,119	240,727
Current liabilities:
Accounts payable	11,911	9,005
Accrued compensation and benefits	13,248	10,410
Accrued expenses	2,417	2,690
Short-term lease liabilities	1,563	1,520
Sales allowances	736	741
Income taxes payable	62	57
Short-term deferred revenue and customer prepayments	8,061	5,507
Total current liabilities	37,998	29,930
Long-term deferred revenue	813	1,054
Contingent consideration obligations	265	451
Long-term income taxes payable	575	567
Long-term lease liabilities	2,880	2,855
Total liabilities	42,531	34,857
Commitments and contingencies (Note 11)
Vicor Corporation stockholders' equity:
Additional paid-in capital	326,026	201,251
Retained earnings	149,815	143,098
Accumulated other comprehensive loss	(203)	(383)
Treasury stock at cost: 11,634,806 shares in 2020 and 2019	(138,927)	(138,927)
Total Vicor Corporation stockholders' equity	337,262	205,562
Noncontrolling interest	326	308
Total equity	337,588	205,870
Total liabilities and equity	380,119	240,727
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	$ 433	$ 405

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Accounts receivable, allowance | $	$ 82	$ 59
Treasury stock, shares	11,634,806	11,634,806
Class B Common Stock [Member]
Common Stock, votes per share	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	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	43,146,143	40,403,058
Common Stock, shares outstanding	31,511,337	28,768,252

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net revenues		$ 78,112	$ 70,772	$ 212,274	$ 199,852
Cost of revenues		44,765	37,770	121,278	106,647
Gross margin		33,347	33,002	90,996	93,205
Operating expenses:
Selling, general and administrative		15,212	15,443	47,036	45,846
Research and development		12,032	11,507	38,197	34,433
Total operating expenses		27,244	26,950	85,233	80,279
Income from operations		6,103	6,052	5,763	12,926
Other income (expense), net:
Total unrealized gains on available-for-sale securities, net		36	11	81	50
Less: portion of gains recognized in other comprehensive income		(35)	(10)	(78)	(47)
Net credit gains recognized in earnings		1	1	3	3
Other income (expense), net		333	145	712	670
Total other income (expense), net		334	146	715	673
Income before income taxes		6,437	6,198	6,478	13,599
Less: Provision (benefit) for income taxes		651	266	(249)	805
Consolidated net income		5,786	5,932	6,727	12,794
Less: Net income (loss) attributable to noncontrolling interest		1	(5)	10	8
Net income attributable to Vicor Corporation		$ 5,785	$ 5,937	$ 6,717	$ 12,786
Net income per common share attributable to Vicor Corporation:
Basic		$ 0.13	$ 0.15	$ 0.16	$ 0.32
Diluted		$ 0.13	$ 0.14	$ 0.15	$ 0.31
Shares used to compute net income per common share attributable to Vicor Corporation:
Basic	[1]	43,164	40,332	41,814	40,279
Diluted		44,743	42,194	43,567	41,435
[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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Consolidated net income		$ 5,786	$ 5,932	$ 6,727	$ 12,794
Foreign currency translation gains (losses), net of tax	[1]	84	(11)	110	74
Unrealized gains on available-for-sale securities, net of tax	[1]	35	10	78	47
Other comprehensive income (loss)		119	(1)	188	121
Consolidated comprehensive income		5,905	5,931	6,915	12,915
Less: Comprehensive income (loss) attributable to noncontrolling interest		7	(6)	18	13
Comprehensive income attributable to Vicor Corporation		$ 5,898	$ 5,937	$ 6,897	$ 12,902
[1]	The deferred tax assets associated with cumulative foreign currency translation gains and cumulative unrealized gains on available-for-sale securities are completely offset by a tax valuation allowance as of September 30, 2020 and 2019. Therefore, there is no income tax benefit (provision) recognized for the three and nine months ended September 30, 2020 and 2019.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
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, 2020	Sep. 30, 2019
Operating activities:
Consolidated net income	$ 6,727	$ 12,794
Adjustments to reconcile consolidated net income to net cash provided by operating activities:
Depreciation and amortization	8,175	7,647
Stock-based compensation expense, net	4,286	2,292
Provision (benefit) for doubtful accounts	23	(138)
Increase (decrease) in long-term income taxes payable	8	(1)
(Decrease) increase in long-term deferred revenue	(241)	902
Gain on disposal of equipment	(9)	(23)
Deferred income taxes	16	24
Credit gain on available-for-sale securities	(3)	(3)
Change in current assets and liabilities, net	(3,742)	(6,955)
Net cash provided by operating activities	15,240	16,539
Investing activities:
Additions to property, plant and equipment	(16,837)	(9,122)
Proceeds from sale of equipment	9	23
Decrease (increase) in other assets	135	(37)
Net cash used for investing activities	(16,693)	(9,136)
Financing activities:
Proceeds from employee stock plans	10,836	3,423
Proceeds from public offering of Common Stock	109,681
Payment of contingent consideration obligations	(186)	(198)
Net cash provided by financing activities	120,331	3,225
Effect of foreign exchange rates on cash	59	44
Net increase in cash and cash equivalents	118,937	10,672
Cash and cash equivalents at beginning of year	84,668	70,557
Cash and cash equivalents at end of year	$ 203,605	$ 81,229

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, 2018	$ 184,090	$ 402	$ 193,457	$ 129,000	$ (394)	$ (138,927)	$ 183,656	$ 434	$ 118
Issuance of Common Stock under employee stock plans	3,423	2	3,421				3,423
Stock-based compensation expense	2,292		2,292				2,292
Other	(4)		(4)				(4)
Components of comprehensive income, net of tax:
Net income (loss)	12,794			12,786			12,786	8
Other comprehensive income (loss)	121				116		116	5
Total comprehensive income (loss)	12,915						12,902	13
Ending Balance at Sep. 30, 2019	202,716	404	199,166	141,786	(278)	(138,927)	202,269	447	118
Beginning Balance at Jun. 30, 2019	194,316	403	196,698	135,849	(278)	(138,927)	193,863	453	118
Issuance of Common Stock under employee stock plans	1,716	1	1,715				1,716
Stock-based compensation expense	753		753				753
Components of comprehensive income, net of tax:
Net income (loss)	5,932			5,937			5,937	(5)
Other comprehensive income (loss)	(1)							(1)
Total comprehensive income (loss)	5,931						5,937	(6)
Ending Balance at Sep. 30, 2019	202,716	404	199,166	141,786	(278)	(138,927)	202,269	447	118
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
Issuance of Common Stock in public offering, net (see Note 5)	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 (loss)	6,727			6,717			6,717	10
Other comprehensive income (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 (see Note 5)	(51)		(51)				(51)
Stock-based compensation expense	1,640		1,640				1,640
Components of comprehensive income, net of tax:
Net income (loss)	5,786			5,785			5,785	1
Other comprehensive income (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

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2020
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, 2020 are not necessarily indicative of the results that may be expected for any other interim period or the year ending December 31, 2020. The balance sheet at December 31, 2019 presented herein has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. For further information, refer to the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K 10-K”).

Inventories

Inventories	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	2. Inventories Inventories are valued at the lower of cost (determined using the first-in, first-out 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 forecasted future usage 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, 2020 December 31, 2019 Raw materials $ 43,165 $ 35,901 Work-in-process 8,090 5,184 Finished goods 6,914 8,102 $ 58,169 $ 49,187

Long-Term Investments

Long-Term Investments	9 Months Ended
	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Long-Term Investments	3. Long-Term Investments As of September 30, 2020 and December 31, 2019, 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, 2020, 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, 2020. The following is a summary of the available-for-sale September 30, 2020 Cost Gross Gross Estimated Failed Auction Security $ 3,000 $ — $ 409 $ 2,591 December 31, 2019 Cost Gross Gross Estimated Failed Auction Security $ 3,000 $ — $ 490 $ 2,510 As of September 30, 2020, the Failed Auction Security had been in an unrealized loss position for greater than 12 months. The amortized cost and estimated fair value of the Failed Auction Security on September 30, 2020, by contractual maturity, are shown below (in thousands): Cost Estimated Due in twenty to forty years $ 3,000 $ 2,591 Based on the fair value measurements described in Note 4, the fair value of the Failed Auction Security on September 30, 2020, with a par value of $3,000,000, was estimated by the Company to be approximately $2,591,000. The gross unrealized loss of $409,000 on the Failed Auction Security consists of two types of estimated loss: an aggregate credit loss of $34,000 and an aggregate temporary impairment of $375,000. 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): 2020 2019 Balance at the beginning of the period $ 37 $ 41 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 $ 34 $ 38 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 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, 2020
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, 2020 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 9,677 $ — $ — $ 9,677 Long-term investments: Failed Auction Security — — 2,591 2,591 Liabilities: Contingent consideration obligations — — (265 ) (265 ) Assets and liabilities measured at fair value on a recurring basis included the following as of December 31, 2019 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 9,630 $ — $ — $ 9,630 Long-term investments: Failed Auction Security — — 2,510 2,510 Liabilities: Contingent consideration obligations — — (451 ) (451 ) As of September 30, 2020, 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, 2020. 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 2019 Form 10-K. Quantitative information about Level 3 fair value measurements as of September 30, 2020 is as follows (dollars in thousands): Fair Value Valuation Unobservable Weighted Failed Auction Security $ 2,591 Discounted cash flow Cumulative probability of earning the maximum rate until maturity 0.11 % Cumulative probability of principal return prior to maturity 94.75 % 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, 2020 was as follows (in thousands): Balance at the beginning of the period $ 2,510 Credit gain on available-for-sale 3 Gain included in Other comprehensive income 78 Balance at the end of the period $ 2,591 The Company has classified its contingent consideration obligations as Level 3 because the fair value for these liabilities was determined using unobservable inputs. The liabilities were based on estimated sales of legacy products over the period of royalty payments at the royalty rate, discounted using the Company’s estimated cost of capital. The change in the estimated fair value calculated for the liabilities valued on a recurring basis utilizing Level 3 inputs (i.e., the Contingent consideration obligations) for the nine months ended September 30, 2020 was as follows (in thousands): Balance at the beginning of the period $ 451 Payments (186 ) Balance at the end of the period $ 265 There were no

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	5. Stockholders’ Equity In June 2020, the Company completed an underwritten public offering of its Common Stock, resulting in the issuance of a total of 1,769,231 shares of registered Common Stock and net proceeds of approximately $109.7 million, after deduction of underwriting discounts and offering expenses. The Company intends to use the net proceeds from the offering to expand its manufacturing facilities and for other general corporate purposes.

Revenues

Revenues	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenues	6. Revenues Revenue from the sale of Advanced Products represents the sum of third-party sales of the products sold under the Advanced Products line, which were sold under the former Picor and VI Chip operating segments during periods prior to the second quarter of 2019. Revenue from the sale of Brick Products represents the sum of third-party sales of the products sold under the Brick Products line, which were also sold under the former Brick Business Unit operating segment, inclusive of such sales of our Vicor Custom Power and Vicor Japan Company, Ltd. subsidiaries. The following tables present the Company’s net revenues disaggregated by geography based on the location of the customer, by product line (in thousands): 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 Three Months Ended September 30, 2019 Brick Products Advanced Products Total United States $ 25,265 $ 4,290 $ 29,555 Europe 5,577 889 6,466 Asia Pacific 14,510 18,875 33,385 All other 1,130 236 1,366 $ 46,482 $ 24,290 $ 70,772 Nine Months Ended September 30, 2019 Brick Products Advanced Products Total United States $ 73,289 $ 16,562 $ 89,851 Europe 17,960 3,517 21,477 Asia Pacific 46,908 37,618 84,526 All other 2,955 1,043 3,998 $ 141,112 $ 58,740 $ 199,852 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, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 40,916 $ 27,422 $ 68,338 Stocking distributors, net of sales allowances 6,661 1,463 8,124 Non-recurring 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 $ 116,127 $ 62,233 $ 178,360 Stocking distributors, net of sales allowances 23,097 6,101 29,198 Non-recurring 414 4,231 4,645 Royalties — 17 17 Other — 54 54 $ 139,638 $ 72,636 $ 212,274 Three Months Ended September 30, 2019 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 39,705 $ 22,574 $ 62,279 Stocking distributors, net of sales allowances 6,522 1,734 8,256 Non-recurring 163 (36 ) 127 Royalties 92 — 92 Other — 18 18 $ 46,482 $ 24,290 $ 70,772 Nine Months Ended September 30, 2019 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 120,496 $ 49,524 $ 170,020 Stocking distributors, net of sales allowances 19,750 7,817 27,567 Non-recurring 762 1,319 2,081 Royalties 104 24 128 Other — 56 56 $ 141,112 $ 58,740 $ 199,852 The following table presents the changes in certain contract assets and (liabilities) (in thousands): September 30, December 31, Change Accounts receivable $ 41,136 $ 38,115 $ 3,021 Short-term deferred revenue and customer prepayments (8,061 ) (5,507 ) (2,554 ) Long-term deferred revenue (813 ) (1,054 ) 241 Deferred expenses 1,588 1,897 (309 ) Sales allowances (736 ) (741 ) 5 The increase in accounts receivable was primarily due to an increase in net revenues of approximately $5,919,000 in September 2020 compared to December 2019. 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 $388,000 and $1,736,000 for the three and nine months ended September 30, 2020, respectively, and $23,000 and $53,000 for the three and nine months ended September 30, 2019, 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, 2020
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	7. 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 2020 2019 2020 2019 Cost of revenues $ 296 $ 86 $ 692 $ 228 Selling, general and administrative 846 482 2,313 1,507 Research and development 498 185 1,281 557 Total stock-based compensation $ 1,640 $ 753 $ 4,286 $ 2,292 Compensation expense by type of award was as follows (in thousands): Three Months Ended Nine Months Ended 2020 2019 2020 2019 Stock options $ 1,420 $ 514 $ 3,663 $ 1,556 ESPP 220 239 623 736 Total stock-based compensation $ 1,640 $ 753 $ 4,286 $ 2,292 The increase in stock option compensation expense for the three and nine months ended September 30, 2020 compared to the three and nine months ended September 30, 2019, was primarily due to an increase in the number of stock options granted and to the acceleration of recognition of compensation expense on stock options granted to retirement eligible employees, both associated with stock option awards in June 2020.

Rental Income

Rental Income	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Rental Income	8. Rental Income Income, net under the Company’s operating lease agreement, for its owned facility leased to a third party in California, was approximately $198,000 and $594,000 for the three and nine months ended September 30, 2020 and 2019, respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes The tax provision (benefit) 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 provision (benefit) for income taxes and the effective income tax rates were as follows (dollars in thousands): Three Months Ended Nine Months Ended 2020 2019 2020 2019 Provision (benefit) for income taxes $ 651 $ 266 $ (249 ) $ 805 Effective income tax rate 10.1 % 4.3 % (3.8 )% 5.9 % The effective tax rates were lower than the statutory tax rates for the three and nine months ended September 30, 2020 and 2019 due primarily to the utilization of tax credits in 2020 and the combination of utilizing net operating loss carryforwards and tax credits in 2019. The net tax benefit for the nine months ended September 30, 2020 reflects the relatively high volume of stock options exercised during the period and the associated impact of excess benefits (and shortfalls) for those stock options exercised, along with the utilization of available tax credits, noted above. The (benefit) provision for income taxes in the three and nine months ended September 30, 2020 and 2019 also included estimated foreign income taxes and estimated state taxes in jurisdictions in which the Company does not have net operating loss carryforwards. As of September 30, 2020, the Company had a valuation allowance of approximately $30,363,000 against all 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 positive operating results in 2018, 2019 and 2020 caused the Company to be in a cumulative income position as of September 30, 2020, its overall profitability has been declining since the third quarter of 2018 and the Company recorded an operating loss in the first quarter of 2020, primarily due to overall reduced bookings for both Advanced and Brick products, reflecting U.S.-China trade/tariff dynamics and elements of macro uncertainty. While the Company recorded modest operating income and bookings increased in both the second and third quarters of 2020, the continued uncertain impact of the COVID-19 COVID-19

Net Income per Share

Net Income per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Income per Share	10. 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 2020 2019 2020 2019 Numerator: Net income attributable to Vicor Corporation $ 5,785 $ 5,937 $ 6,717 $ 12,786 Denominator: Denominator for basic net income per share-weighted average shares (1) 43,164 40,332 41,814 40,279 Effect of dilutive securities: Employee stock options (2) 1,579 1,862 1,753 1,156 Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions 44,743 42,194 43,567 41,435 Basic net income per share $ 0.13 $ 0.15 $ 0.16 $ 0.32 Diluted net income per share $ 0.13 $ 0.14 $ 0.15 $ 0.31 (1) Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding. (2) Options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, and 171,499 and 138,251 shares of Common Stock for the three and nine months ended September 30, 2019, 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, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies At September 30, 2020, the Company had approximately $12,595,000 of capital expenditure commitments, principally for manufacturing equipment. In addition to these commitments, the Company had, in aggregate, approximately $63,800,000 of budgeted capital expenditures associated with the construction of a 90,000 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. On May 23, 2016, after extensive discovery, the Texas Action was stayed by the court pending completion of certain inter partes reexamination (“IPRx”) proceedings at the United States Patent and Trademark Office (“USPTO”) (including any appeals from such proceedings to the Federal Circuit (as defined below)) concerning the SynQor patents, which are described below. That stay remains in force. In 2011, in response to the filing of the Texas Action, the Company’s IPRx proceedings at the USPTO challenged the validity of all claims that were asserted against the Company by SynQor. The current status of these proceedings is as follows. Regarding the ‘190 patent IPRx, the United States Court of Appeals for the Federal Circuit (the “Federal Circuit”) issued a decision on March 13, 2015, determining that certain claims were invalid and remanding the matter to the Patent Trial and Appeal Board (“PTAB”) of the USPTO for further proceedings. On February 20, 2019, the PTAB issued a decision finding that all of the remaining challenged claims were unpatentable. SynQor has appealed that decision to the Federal Circuit, and the appeal remains pending. On August 30, 2017, the Federal Circuit issued rulings with regard to the IPRx proceedings for the ’021, ‘702 and ‘290 patents. With respect to the ‘021 patent, the Federal Circuit affirmed the PTAB’s determination that all of the challenged claims of the ‘021 patent were invalid. The Federal Circuit remanded the case to the PTAB for further consideration of the patentability of certain claims that had been added by amendment during the reexamination. On February 20, 2019, the PTAB issued a decision affirming the examiner’s rejections of all challenged claims. SynQor has filed an appeal of that decision in the Federal Circuit. That appeal has been stayed pending resolution of the pending appeal regarding the ‘190 patent IPRx. With respect to the ‘702 patent, the Federal Circuit affirmed the PTAB’s determination that all of the challenged claims of the ‘702 patent were patentable. With respect to the ‘290 patent, the Federal Circuit vacated the PTAB’s decision upholding the patentability of the ‘290 patent claims, and remanded the case to the PTAB for further consideration. On February 20, 2019, the PTAB issued a decision reversing its prior affirmance of the examiner’s non-adoption On October 31, 2017, the Company filed a request with the USPTO for ex parte reexamination (“EPRx”) of the asserted claims of the ‘702 patent, based on different prior art references than had been at issue in the previous IPRx of the ‘702 patent. On September 12, 2018, a patent examiner found that all of the asserted claims were invalid. SynQor has appealed that ruling to the PTAB, where the appeal remains pending. On August 6, 2018, the Company filed a request with the USPTO for EPRx of the asserted claims of the ‘190 patent, based on different prior art references than had been at issue in the previous IPRx of the ‘190 patent. On August 9, 2019, the USPTO issued a final rejection of all of the asserted claims of the ‘190 patent. SynQor has appealed that ruling to the PTAB, where the appeal 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, 2020
Accounting Changes and Error Corrections [Abstract]
Impact of Recently Issued Accounting Standards	12. 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 will be effective for the Company for its fiscal year beginning after December 15, 2020, with early adoption permitted. The Company has not yet determined the impact this new guidance will have on its consolidated financial statements and disclosures. In August 2018, the FASB issued guidance which modifies the disclosure requirements on fair value measurements under Topic 820, Fair Value Measurements, including the consideration of costs and benefits. The new guidance is effective for all entities for annual and interim periods in fiscal years beginning after December 15, 2019, with early adoption permitted. It is required to be applied on a retrospective approach with certain elements being adopted prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. The Company adopted the new guidance as of January 1, 2020. The adoption did not have a material impact on the Company’s consolidated financial statements and disclosures. In June 2016, the FASB issued guidance which requires measurement and recognition of expected credit losses on certain types of financial instruments. It also modifies the impairment model for available-for-sale Other new pronouncements issued but not effective until after September 30, 2020 are not expected to have a material impact on the Company’s consolidated financial statements.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories were as follows (in thousands): September 30, 2020 December 31, 2019 Raw materials $ 43,165 $ 35,901 Work-in-process 8,090 5,184 Finished goods 6,914 8,102 $ 58,169 $ 49,187

Long-Term Investments (Tables)

Long-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following is a summary of the available-for-sale September 30, 2020 Cost Gross Gross Estimated Failed Auction Security $ 3,000 $ — $ 409 $ 2,591 December 31, 2019 Cost Gross Gross Estimated Failed Auction Security $ 3,000 $ — $ 490 $ 2,510
Cost and Estimated Fair Value of Failed Auction Security by Contractual Maturities	The amortized cost and estimated fair value of the Failed Auction Security on September 30, 2020, by contractual maturity, are shown below (in thousands): Cost Estimated Due in twenty to forty years $ 3,000 $ 2,591
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): 2020 2019 Balance at the beginning of the period $ 37 $ 41 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 $ 34 $ 38

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 9,677 $ — $ — $ 9,677 Long-term investments: Failed Auction Security — — 2,591 2,591 Liabilities: Contingent consideration obligations — — (265 ) (265 ) Assets and liabilities measured at fair value on a recurring basis included the following as of December 31, 2019 (in thousands): Using Quoted Prices Significant Significant Total Fair Cash equivalents: Money market funds $ 9,630 $ — $ — $ 9,630 Long-term investments: Failed Auction Security — — 2,510 2,510 Liabilities: Contingent consideration obligations — — (451 ) (451 )
Quantitative Information about Level 3 Fair Value Measurements	Quantitative information about Level 3 fair value measurements as of September 30, 2020 is as follows (dollars in thousands): Fair Value Valuation Unobservable Weighted Failed Auction Security $ 2,591 Discounted cash flow Cumulative probability of earning the maximum rate until maturity 0.11 % Cumulative probability of principal return prior to maturity 94.75 % 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, 2020 was as follows (in thousands): Balance at the beginning of the period $ 2,510 Credit gain on available-for-sale 3 Gain included in Other comprehensive income 78 Balance at the end of the period $ 2,591
Change in Estimated Fair Value Calculated for Liabilities Valued on Recurring Basis Utilizing Level 3 Inputs	The change in the estimated fair value calculated for the liabilities valued on a recurring basis utilizing Level 3 inputs (i.e., the Contingent consideration obligations) for the nine months ended September 30, 2020 was as follows (in thousands): Balance at the beginning of the period $ 451 Payments (186 ) Balance at the end of the period $ 265

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2020
Summary of Net Revenues Based On Geography Location	The following tables present the Company’s net revenues disaggregated by geography based on the location of the customer, by product line (in thousands): 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 Three Months Ended September 30, 2019 Brick Products Advanced Products Total United States $ 25,265 $ 4,290 $ 29,555 Europe 5,577 889 6,466 Asia Pacific 14,510 18,875 33,385 All other 1,130 236 1,366 $ 46,482 $ 24,290 $ 70,772 Nine Months Ended September 30, 2019 Brick Products Advanced Products Total United States $ 73,289 $ 16,562 $ 89,851 Europe 17,960 3,517 21,477 Asia Pacific 46,908 37,618 84,526 All other 2,955 1,043 3,998 $ 141,112 $ 58,740 $ 199,852
Summary of Net Revenues Disaggregated by Category	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, 2020 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 40,916 $ 27,422 $ 68,338 Stocking distributors, net of sales allowances 6,661 1,463 8,124 Non-recurring 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 $ 116,127 $ 62,233 $ 178,360 Stocking distributors, net of sales allowances 23,097 6,101 29,198 Non-recurring 414 4,231 4,645 Royalties — 17 17 Other — 54 54 $ 139,638 $ 72,636 $ 212,274 Three Months Ended September 30, 2019 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 39,705 $ 22,574 $ 62,279 Stocking distributors, net of sales allowances 6,522 1,734 8,256 Non-recurring 163 (36 ) 127 Royalties 92 — 92 Other — 18 18 $ 46,482 $ 24,290 $ 70,772 Nine Months Ended September 30, 2019 Brick Products Advanced Products Total Direct customers, contract manufacturers and non-stocking $ 120,496 $ 49,524 $ 170,020 Stocking distributors, net of sales allowances 19,750 7,817 27,567 Non-recurring 762 1,319 2,081 Royalties 104 24 128 Other — 56 56 $ 141,112 $ 58,740 $ 199,852
Summary of Changes in Contract Assets And Liabilities	The following table presents the changes in certain contract assets and (liabilities) (in thousands): September 30, December 31, Change Accounts receivable $ 41,136 $ 38,115 $ 3,021 Short-term deferred revenue and customer prepayments (8,061 ) (5,507 ) (2,554 ) Long-term deferred revenue (813 ) (1,054 ) 241 Deferred expenses 1,588 1,897 (309 ) Sales allowances (736 ) (741 ) 5

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Stock-Based Compensation Expense	Stock-based compensation expense was as follows (in thousands): Three Months Ended Nine Months Ended 2020 2019 2020 2019 Cost of revenues $ 296 $ 86 $ 692 $ 228 Selling, general and administrative 846 482 2,313 1,507 Research and development 498 185 1,281 557 Total stock-based compensation $ 1,640 $ 753 $ 4,286 $ 2,292
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 2020 2019 2020 2019 Stock options $ 1,420 $ 514 $ 3,663 $ 1,556 ESPP 220 239 623 736 Total stock-based compensation $ 1,640 $ 753 $ 4,286 $ 2,292

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision for Income Taxes and Effective Income Tax Rates	The provision (benefit) for income taxes and the effective income tax rates were as follows (dollars in thousands): Three Months Ended Nine Months Ended 2020 2019 2020 2019 Provision (benefit) for income taxes $ 651 $ 266 $ (249 ) $ 805 Effective income tax rate 10.1 % 4.3 % (3.8 )% 5.9 %

Net Income per Share (Tables)

Net Income per Share (Tables)	9 Months Ended
	Sep. 30, 2020
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 2020 2019 2020 2019 Numerator: Net income attributable to Vicor Corporation $ 5,785 $ 5,937 $ 6,717 $ 12,786 Denominator: Denominator for basic net income per share-weighted average shares (1) 43,164 40,332 41,814 40,279 Effect of dilutive securities: Employee stock options (2) 1,579 1,862 1,753 1,156 Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions 44,743 42,194 43,567 41,435 Basic net income per share $ 0.13 $ 0.15 $ 0.16 $ 0.32 Diluted net income per share $ 0.13 $ 0.14 $ 0.15 $ 0.31 (1) Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding. (2) Options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, and 171,499 and 138,251 shares of Common Stock for the three and nine months ended September 30, 2019, 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, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 43,165	$ 35,901
Work-in-process	8,090	5,184
Finished goods	6,914	8,102
Net balance	$ 58,169	$ 49,187

Long-Term Investments - Additio

Long-Term Investments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Unrealized Losses On Short Term And Long Term Investments [Line Items]
Minimum period for which failed auction securities been in unrealized loss position	12 months
Aggregate credit loss			$ 38,000	$ 41,000
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	$ 2,591,000	2,510,000
Gross Unrealized Losses	409,000	490,000
Aggregate credit loss	34,000	$ 37,000
Aggregate temporary impairment loss	$ 375,000

Long-Term Investments - Summary

Long-Term Investments - Summary of Available-for-Sale Securities (Detail) - Failed Auction Security [Member] - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cost	$ 3,000,000	$ 3,000,000
Gross Unrealized Losses	409,000	490,000
Estimated Fair Value	$ 2,591,000	$ 2,510,000

Long-Term Investments - Amortiz

Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) $ in Thousands	Sep. 30, 2020USD ($)
Available-for-sale Securities, Debt Maturities [Abstract]
Due in twenty to forty years, Cost	$ 3,000
Due in twenty to forty years, Estimated Fair Value	$ 2,591

Long-Term Investments - Rollfor

Long-Term Investments - Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Balance at the beginning of the period		$ 41,000
Reductions in the amount related to credit gain for which other-than-temporary impairment was not previously recognized		(3,000)
Balance at the end of the period		$ 38,000
Failed Auction Security [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Balance at the beginning of the period	$ 37,000
Reductions in the amount related to credit gain for which other-than-temporary impairment was not previously recognized	(3,000)
Balance at the end of the period	$ 34,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Contingent Consideration Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities, fair value on recurring basis	$ (265,000)	$ (451,000)
Failed Auction Security [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Estimated Fair Value	2,591,000	2,510,000
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	9,677,000	9,630,000
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	9,677,000	9,630,000
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	(265,000)	(451,000)
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	$ 2,591,000	$ 2,510,000

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, 2020USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,591
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	0.11%
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	94.75%
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, 2020USD ($)
Fair Value Disclosures [Abstract]
Balance at the beginning of the period	$ 2,510
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	$ 2,591

Fair Value Measurements - Cha_2

Fair Value Measurements - Change in Estimated Fair Value Calculated for Liabilities Valued on Recurring Basis Utilizing Level 3 Inputs (Detail) - Significant Unobservable Inputs (Level 3) [Member] - Contingent Consideration Obligations [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at the beginning of the period	$ 451
Payments	(186)
Balance at the end of the period	$ 265

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	Sep. 30, 2020USD ($)
Fair Value Disclosures [Abstract]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 0

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - Underwritten Public Offer [Member] $ in Millions	1 Months Ended
	Jun. 30, 2020USD ($)shares
Stockholders Equity [Line Items]
Common stock shares issued during the period | shares	1,769,231
Sale of common stock share net amount of inflows | $	$ 109.7

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 78,112	$ 70,772	$ 212,274	$ 199,852
Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	47,693	46,482	139,638	141,112
Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	30,419	24,290	72,636	58,740
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	21,296	29,555	75,085	89,851
United States [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	16,905	25,265	57,880	73,289
United States [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	4,391	4,290	17,205	16,562
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	6,506	6,466	23,669	21,477
Europe [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	4,456	5,577	18,451	17,960
Europe [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	2,050	889	5,218	3,517
Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenue	49,804	33,385	110,993	84,526
Asia Pacific [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	25,878	14,510	60,917	46,908
Asia Pacific [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	23,926	18,875	50,076	37,618
All Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	506	1,366	2,527	3,998
All Other [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	454	1,130	2,390	2,955
All Other [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 52	$ 236	$ 137	$ 1,043

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 78,112	$ 70,772	$ 212,274	$ 199,852
Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	47,693	46,482	139,638	141,112
Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	30,419	24,290	72,636	58,740
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member]
Disaggregation of Revenue [Line Items]
Revenue	68,338	62,279	178,360	170,020
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	40,916	39,705	116,127	120,496
Direct Customers, Contract Manufacturers and Non-stocking Distributors [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	27,422	22,574	62,233	49,524
Stocking Distributors, Net of Sales Allowances [Member]
Disaggregation of Revenue [Line Items]
Revenue	8,124	8,256	29,198	27,567
Stocking Distributors, Net of Sales Allowances [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	6,661	6,522	23,097	19,750
Stocking Distributors, Net of Sales Allowances [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,463	1,734	6,101	7,817
Non-recurring Engineering [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,615	127	4,645	2,081
Non-recurring Engineering [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	116	163	414	762
Non-recurring Engineering [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,499	(36)	4,231	1,319
Royalties [Member]
Disaggregation of Revenue [Line Items]
Revenue	17	92	17	128
Royalties [Member] | Brick Products [Member]
Disaggregation of Revenue [Line Items]
Revenue		92		104
Royalties [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	17		17	24
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	18	18	54	56
Other [Member] | Advanced Products [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 18	$ 18	$ 54	$ 56

Revenues - Summary of Changes i

Revenues - Summary of Changes in Certain Contract Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Accounts receivable	$ 41,136	$ 38,115
Short-term deferred revenue and customer prepayments	(8,061)	(5,507)
Long-term deferred revenue	(813)	(1,054)
Deferred expenses	1,588	1,897
Sales allowances	(736)	$ (741)
Accounting Standards Update 2014-09 [Member]
Disaggregation of Revenue [Line Items]
Accounts receivable	3,021
Short-term deferred revenue and customer prepayments	(2,554)
Long-term deferred revenue	241
Deferred expenses	(309)
Sales allowances	$ 5

Revenues - Additional Informati

Revenues - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase in net revenues			$ 5,919,000
Deferred Revenue, Revenue Recognized	$ 388,000	$ 23,000	$ 1,736,000	$ 53,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,640	$ 753	$ 4,286	$ 2,292
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	296	86	692	228
Selling, General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	846	482	2,313	1,507
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 498	$ 185	$ 1,281	$ 557

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,640	$ 753	$ 4,286	$ 2,292
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,420	514	3,663	1,556
ESPP [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 220	$ 239	$ 623	$ 736

Rental Income - Additional info

Rental Income - Additional information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Lease income	$ 198,000	$ 594,000	$ 198,000	$ 594,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	Sep. 30, 2020USD ($)
Income Tax Disclosure [Line Items]
Valuation allowance, deferred tax assets	$ 30,363,000

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes	$ 651	$ 266	$ (249)	$ 805
Effective income tax rate	10.10%	4.30%	(3.80%)	5.90%

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income attributable to Vicor Corporation		$ 5,785	$ 5,937	$ 6,717	$ 12,786
Denominator:
Denominator for basic net income per share-weighted average shares	[1]	43,164	40,332	41,814	40,279
Effect of dilutive securities:
Employee stock options	[2]	1,579	1,862	1,753	1,156
Denominator for diluted net income per share – adjusted weighted-average shares and assumed conversions		44,743	42,194	43,567	41,435
Basic net income per share		$ 0.13	$ 0.15	$ 0.16	$ 0.32
Diluted net income per share		$ 0.13	$ 0.14	$ 0.15	$ 0.31
[1]	Denominator represents weighted average number of shares of Common Stock and Class B Common Stock outstanding.
[2]	Options to purchase 265,725 and 130,027 shares of Common Stock for the three and nine months ended September 30, 2020, respectively, and 171,499 and 138,251 shares of Common Stock for the three and nine months ended September 30, 2019, 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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Options to purchase shares of Common Stock not included in the computation of diluted income per share	265,725	171,499	130,027	138,251

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Sep. 30, 2020USD ($)ft²
Commitments and Contingencies Disclosure [Abstract]
Capital expenditure commitments	$ 12,595,000
Budgeted capital expenditures	$ 63,800,000
Area of Land | ft²	90,000