Liabilities - Restructuring accruals general information (Details) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2016 USD ($) employee	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) employee	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Restructuring accruals
Restructuring	$ 1,798	$ 469		$ 3,993	$ 3,509
Minimum
Restructuring accruals
Additional restructuring costs expected over the next few quarters	4,000		$ 4,000	4,000
Maximum
Restructuring accruals
Additional restructuring costs expected over the next few quarters	$ 7,000		7,000	$ 7,000
Streamline operations, enhance efficiency and reduce costs
Restructuring accruals
Restructuring			$ 2,900
Atomic layer deposition restructuring plan
Restructuring accruals
Number of employees impacted | employee	25
Personnel severance and related costs | Streamline operations, enhance efficiency and reduce costs
Restructuring accruals
Number of employees impacted | employee			50
Restructuring			$ 2,800
Personnel severance and related costs | Atomic layer deposition restructuring plan
Restructuring accruals
Restructuring	$ 900
Facility closing costs | Streamline operations, enhance efficiency and reduce costs
Restructuring accruals
Restructuring			$ 100