Share-based Compensation Expense

Share-based compensation expense for all stock awards consists of the following (in millions):
 
Years Ended
 
December 31,
2017
 
January 1,
2017
 
January 3,
2016
Cost of product revenue
$
12

 
$
9

 
$
10

Cost of service and other revenue
2

 
2

 
2

Research and development
51

 
42

 
42

Selling, general and administrative
99

 
76

 
79

Share-based compensation expense before taxes
164

 
129

 
133

Related income tax benefits
(48
)
 
(41
)
 
(39
)
Share-based compensation expense, net of taxes
$
116

 
$
88

 
$
94



The assumptions used for the specified reporting periods and the resulting estimates of weighted-average fair value per share for stock purchased under the ESPP are as follows:
 
Years Ended
 
December 31,
2017
 
January 1,
2017
 
January 3,
2016
Risk-free interest rate
0.50% - 1.22%

 
0.40% - 0.50%

 
0.07% - 0.33%

Expected volatility
29% - 44%

 
40% - 44%

 
29% - 38%

Expected term
0.5 - 1.0 year

 
0.5 - 1.0 year

 
0.5 - 1.0 year

Expected dividends
0
%
 
0
%
 
0
%
Weighted-average grant-date fair value per share
$
46.81

 
$
48.29

 
$
53.92



As of December 31, 2017, approximately $394 million of total unrecognized compensation cost related to restricted stock and ESPP shares issued to date are expected to be recognized over a weighted-average period of approximately 2.7 years.

Historical Timeline

Fiscal YearFiled
2017Feb 13, 2018Showing above
2016Mar 2, 2016

About Stock Compensation Disclosures

Stock-based compensation disclosures detail the equity awards granted to employees and executives — including stock options, restricted stock units (RSUs), and performance shares — along with the valuation methods and assumptions used to expense them. This section reveals the true cost of talent retention and the alignment between management incentives and shareholder interests.

Key signals: total unrecognized compensation expense and its expected recognition period signal future earnings headwinds from already-granted awards. For stock options, examine Black-Scholes assumptions — expected volatility, risk-free rate, and expected term — as understating any of these reduces reported compensation expense. Compare stock compensation expense as a percentage of revenue against peers to assess dilution cost. Watch vesting schedules for acceleration clauses tied to change-of-control events. Performance-based awards with undemanding targets may indicate weak governance. Add back stock compensation to operating cash flow to calculate a more conservative free cash flow figure.