Stock-Based Compensation

12 Months Ended

Dec. 30, 2017

Stock-Based Compensation Expense

Certain information regarding our stock-based compensation was as follows (in thousands, except per share amounts):



	Fiscal Year Ended
	December 30, 2017		December 31, 2016		December 26, 2015
Weighted average grant date per share fair value of stock options granted	$	—	$	2.00	$	3.80
Weighted average grant date per share fair value of RSUs granted	13.20		8.20		8.64
Total intrinsic value of stock options exercised	5,946		558		22
Fair value of RSUs vested	18,339		12,441		18,118

Stock-based compensation expense was included in the Consolidated Statement of Operations as follows (in thousands):



	Fiscal Year Ended
	December 30, 2017		December 31, 2016		December 26, 2015
Stock-based compensation expense included in:
Cost of revenues	$	3,539	$	2,518	$	2,651
Research and development	5,341		3,329		3,490
Selling, general and administrative	7,350		4,875		5,434
Restructuring and impairment charges, net	109		964		500
Total stock-based compensation	$	16,339	$	11,686	$	12,075

Unrecognized Stock-Based Compensation Expense

Unrecognized stock-based compensation expense at December 30, 2017 consisted of the following (in thousands):

Valuation Assumptions

The following assumptions were used in estimating the fair value of options awarded and Employee Stock Purchase Plan:



	Fiscal Year Ended
	December 30, 2017		December 31, 2016		December 26, 2015
2012 Equity Incentive Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	—	%	43.76	%	47.50	%
Risk-free interest rate	—	%	1.57	%	1.60	%
Expected life (in years)	—		5.5		5.5

Employee Stock Purchase Plan:
Dividend yield	—	%	—	%	—	%
Expected volatility	46.20%-46.33%		43.76%-46.48%		45.95%-54.69%
Risk-free interest rate	0.65%-1.15%		0.40%-0.47%		0.07%-0.17%
Expected life (in years)	0.5-1.0		0.5-1.0		0.5-1.0

Weighted Average Recognition Period (Years)

Stock Options