Stock-Based Compensation

3 Months Ended

Apr. 01, 2017

Share-based Compensation [Abstract]

Stock-Based Compensation

Stock-Based Compensation

Stock-based compensation expenses recognized under ASC Topic 718, Compensation – Stock Compensation (“ASC 718”), for employees and directors and the effect on our Condensed Consolidated Statements of Operations were as follows:

	Three Months Ended
(In thousands)	April 1, 2017		April 2, 2016
Cost of sales	$	174	$	187
Research, development, and engineering	807		801
Selling, general and administrative expenses	2,211		2,491
Total stock-based compensation expense	$	3,192	$	3,479

Stock-based compensation cost capitalized as part of inventory during the three month periods ended April 1, 2017 and April 2, 2016 was $0.1 million.

As required by ASC 718, we estimate expected forfeitures and recognize compensation costs only for those equity awards expected to vest. As of April 1, 2017, there was $27.9 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements granted under our 1993 Stock Option Plan/Stock Issuance Plan, as amended (the “1993 Plan”). The costs related to stock options and restricted stock units are expected to be recognized over a weighted average period of 2.79 years.

The 1993 Plan provides for the grant of stock-based awards to our eligible employees, consultants and advisers and non-employee directors. As of April 1, 2017, there were insignificant shares reserved for future awards under the 1993 Plan.

We used the following weighted-average assumptions to estimate the fair value of our stock options granted:

	Three Months Ended
	April 1, 2017	April 2, 2016
Expected life (in years)	N/A	5.9
Risk-free interest rate	N/A	1.7%
Volatility	N/A	43%
Dividend yield	N/A	—%

Our equity awards granted during the three months period ended April 1, 2017 and the corresponding period of 2016 were granted with vesting terms of 50 months.