Stock-Based Compensation and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Stock-based compensation expense for the years ended December 31 was as follows (in thousands):


	2017		2016			2015
Cost of revenues	$	187	$	95		$	230
Selling, general and administrative		1,125		412			1,246
Research and development		423		(1	)		306

Total stock-based compensation	$	1,735	$	506		$	1,782

Summary of Compensation Expense by Type of Award

Compensation expense by type of award for the years ended December 31 was as follows (in thousands):


	2017		2016		2015
Stock options	$	1,546	$	506	$	1,782
ESPP		189		—		—

Total stock-based compensation	$	1,735	$	506	$	1,782

Weighted-Average Assumptions for Non Performance-Based Fair Value for Stock Options

The fair value for non performance-based stock options awarded for the years shown below was estimated at the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:


Vicor:	2017			2016			2015
Risk-free interest rate		2.1	%		1.5	%		2.0	%
Expected dividend yield		—			—			—
Expected volatility		43	%		45	%		51	%
Expected lives (years)		7.1			7.2			7.2

VI Chip:	2017			2016			2015
Risk-free interest rate		1.9	%		1.7	%		2.1	%
Expected dividend yield		—			—			—
Expected volatility		32	%		34	%		37	%
Expected lives (years)		6.5			6.5			6.5

Picor:	2017			2016			2015
Risk-free interest rate		1.9	%		1.5	%		1.9	%
Expected dividend yield		—			—			—
Expected volatility		48	%		42	%		41	%
Expected lives (years)		6.5			6.5			6.5

2000 Plan, Vicor [Member]

Stock-Based Compensation Expense

A summary of the activity under the 2000 Plan as of December 31, 2017 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):


	Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
Outstanding on December 31, 2016		1,696,222		$	8.82
Granted		96,322		$	18.41
Forfeited and expired		(25,087	)	$	10.92
Exercised		(401,540	)	$	8.21

Outstanding on December 31, 2017		1,365,917		$	9.63		6.21	$	15,409

Exercisable on December 31, 2017		707,244		$	8.01		5.82	$	9,116

Vested or expected to vest as of December 31, 2017(1)		1,332,671		$	9.54		6.19	$	15,161

(1)	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. The number of options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.

Picor Plan [Member]

Stock-Based Compensation Expense

A summary of the activity under the 2001 Picor Plan as of December 31, 2017 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):


	Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
Outstanding on December 31, 2016		9,530,987		$	0.62
Granted		673,000		$	0.62
Forfeited and expired		(126,000	)	$	0.73
Exercised		(12,000	)	$	0.41

Outstanding on December 31, 2017		10,065,987		$	0.62		3.80	$	493

Exercisable on December 31, 2017		8,384,987		$	0.61		3.31	$	400

Vested or expected to vest as of December 31, 2017(1)		9,996,810		$	0.62		3.78	$	492

(1)	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.

Vi Chip Plan [Member]

Stock-Based Compensation Expense

A summary of the activity under the 2007 VI Chip Plan as of December 31, 2017 and changes during the year then ended, is presented below (in thousands except for share and weighted-average data):


	Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
Outstanding on December 31, 2016		9,933,750		$	1.00
Granted		9,771,500		$	0.96
Forfeited and expired		(6,613,000	)	$	1.00
Exercised		—		$	—

Outstanding on December 31, 2017 (1)		13,092,250		$	0.97		5.78	$	—

Exercisable on December 31, 2017		810,700		$	1.00		4.46	$	—

Vested or expected to vest as of December 31, 2017(2)		11,210,701		$	0.97		5.67	$	—

(1)	Of the total VI Chip options outstanding on December 31, 2017, 5,500,000 options had been granted to Dr. Vinciarelli, the Company’s Chief Executive Officer.

(2)	In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.