Research and Development Expenses (Tables)

3 Months Ended

Mar. 31, 2017

Research and Development Expenses

Schedule of research and development expenses

	Three Months Ended March 31,
(in thousands)	2016		2017
Research materials and purchased services	$	10,184	$	9,608
Staff costs	1,985		2,320
Other research and development expenses	838		699
Depreciation and amortization	29		33
Total	$	13,036	$	12,660