Stockholders' Equity and Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share repurchases

Shares repurchased and retired for fiscal year 2015 and 2014 of the applicable repurchase programs, with the associated cost of repurchase and amount available for repurchase at the end of the respective periods are as follows (in thousands, except number of shares and weighted average price per share):

	Fiscal Year 2015		Fiscal Year 2014
Number of shares of common stock repurchased		111,050		362,633
Weighted average price per share	$	15.49	$	14.74
Total cost of repurchase	$	1,721	$	5,344
Amount available for repurchase at end of period	$	4,397	$	6,118

Option plans

The Nanometrics option plans are as follows:

Plan Name	Participants	Shares Authorized
2005 Equity Incentive Plan	Employees, consultants and directors		7,292,594
2002 Non-statutory Stock Option Plan	Employees and consultants		1,200,000
2000 Employee Stock Option Plan	Employees and consultants		2,450,000
2000 Director Stock Option Plan	Non-employee directors		250,000
Accent Optical Technologies, Inc. Stock Incentive Plan	Employees and consultants		205,003

Stock options and employee stock purchase plan assumptions

The weighted-average fair value calculations are based on the following average assumptions:

	Fiscal Year 2016			Fiscal Year 2015			Fiscal Year 2014
Stock Options:
Expected life		—			—		4.6 years
Volatility		—			—			54.9	%
Risk free interest rate		—			—			1.54	%
Dividends		—			—			—
Employee Stock Purchase Plan:
Expected life	0.5 years			0.5 years			0.5 years
Volatility		38.7	%		36.9	%		31.2	%
Risk free interest rate		0.44	%		0.12	%		0.54	%
Dividends		—			—			—

Stock option plans activity

A summary of activity of stock options is as follows:

	Number of Shares Outstanding (Options)			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in Thousands)
Options
Outstanding at December 27, 2014		1,382,993		$	13.92		3.41	$	4,108
Exercised		(229,510	)		9.65
Cancelled/Forfeited		(94,012	)		16.67
Outstanding at December 26, 2015		1,059,471			14.61		2.47	$	1,920
Exercised		(442,339	)		13.66
Cancelled/Forfeited		(176,587	)		15.83
Outstanding at December 31, 2016		440,545			15.06		2.12	$	4,405
Exercisable at December 31, 2016		407,920		$	14.94		2.00	$	4,129

Ranges of outstanding and exercisable options

The following table summarizes ranges of outstanding and exercisable options as of December 31, 2016.

	Options Outstanding						Options Exercisable
Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$9.5-$10.46		17,400		0.32	$	10.05		17,400	$	10.05
$11.37-$11.37		114,166		0.88		11.37		114,166		11.37
$12.98-$15.33		45,691		3.01		14.36		38,954		14.34
$15.35-$15.74		44,437		2.58		15.65		40,586		15.65
$15.85-$15.85		60,000		3.19		15.85		56,250		15.85
$15.97-$17.33		57,166		2.30		16.89		48,527		16.85
$17.7-$18.27		36,935		2.34		18.12		33,267		18.15
$18.51-$18.51		13,750		4.13		18.51		8,333		18.51
$18.79-$18.79		1,000		4.23		18.79		437		18.79
$19.03-$19.03		50,000		2.13	$	19.03		50,000	$	19.03
$9.5-$19.03		440,545						407,920

Summary of activity for RSUs

A summary of activity for RSUs is as follows:

Summary of activity for RSUs	Number of RSUs			Weighted Average Fair Value
Outstanding RSUs as of December 27, 2014		563,337		$	17.90
Granted		506,459			15.62
Released		(237,520	)		16.59
Cancelled		(119,033	)		16.59
Outstanding RSUs as of December 26, 2015		713,243			15.99
Granted		476,667			17.45
Released		(315,872	)		16.05
Cancelled		(54,253	)		16.29
Outstanding RSUs as of December 31, 2016		819,785		$	16.79

Summary of activity for PSUs

A summary of activity for PSUs is as follows:

Summary of activity for PSUs	Number of PSUs			Weighted Average Fair Value
Outstanding PSUs as of December 27, 2014		—			—
Granted		60,000		$	12.23
Outstanding PSUs as of December 26, 2015		60,000			12.23
Granted		67,500			8.52
Released		(13,333	)		12.03
Cancelled		(6,667	)		12.03
Outstanding PSUs as of December 31, 2016		107,500		$	9.94

PSUs valuation assumptions

The assumptions for the valuation of PSUs are summarized as follows:

	2016 Award		2015 Award
Grant Date Fair Value Per Share	$	8.52	$	12.23
Weighted-average assumptions/inputs:
Expected Dividend		—		—
Range of risk-free interest rates		0.92%	0.25%-1.1%
Range of expected volatilities for peer group	22%-93%		23%-65%

Stock-based compensation expense for all share-based payment awards

Stock-based compensation expense for all share-based payment awards made to the Company’s employees and directors pursuant to the employee stock option and employee stock purchase plans by function were as follows (in thousands):

	Fiscal Year 2016		Fiscal Year 2015		Fiscal Year 2014
Cost of products	$	403	$	274	$	268
Cost of service		509		309		287
Research and development		1,408		1,036		1,245
Selling		2,046		1,881		1,642
General and administrative		3,300		2,748		3,243
Restructuring		—		—		67
Total stock-based compensation expense related to    employee stock options and employee stock purchases	$	7,666	$	6,248	$	6,752

Stock Options, RSUs and PSUs [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock option plans activity including options, RSUs and PSUs

A summary of activity under the Company’s stock option plans including options, RSUs and PSUs during fiscal year 2016, 2015 and 2014 and shares available for grant as of the respective period end dates, is as follows:

	Fiscal Year 2016			Fiscal Year 2015			Fiscal Year 2014
Shares available for grant at beginning of fiscal year		1,916,589			2,464,082			2,937,001
Options - granted		—			—			(74,300	)
Options - cancelled		176,587			94,012			191,061
Options - expired plan shares		(116,192	)		(1,800	)		(17,491	)
RSUs - granted		(810,334	)		(860,980	)		(805,120	)
RSUs - cancelled		92,230			202,356			167,404
RSUs - shares issued to satisfy tax    withholding obligations		179,117			120,919			65,527
PSUs - granted		(114,750	)		(102,000	)
PSUs - cancelled		11,334			—			—
Shares available for grant at end of fiscal year		1,334,581			1,916,589			2,464,082