Stock-based compensation (Tables)

3 Months Ended

Mar. 31, 2018

Share-based Compensation [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

The following table sets forth the stock-based compensation expense recognized in the Consolidated Statements of Income (in thousands):

	Three Months Ended March 31,
	2018		2017
Cost of goods sold	$	695	$	400
Research and development	1,409		1,177
Selling, general and administrative	3,827		4,669
Stock-based compensation expense before income taxes	$	5,931	$	6,246

Stock-based compensation expense capitalized in the Consolidated Balance Sheets is as follows (in thousands):

	March 31,
	2018		2017
Capitalized in inventory	$	1,057	$	902