Revenue recognition - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue recognition
Revenue	$ 13,130	$ 13,536	$ 28,857	$ 25,872
Product revenue
Revenue recognition
Revenue	6,790	8,776	16,623	18,322
Product revenue | NA
Revenue recognition
Revenue	2,954	4,814	7,631	9,830
Product revenue | EMEA
Revenue recognition
Revenue	2,906	2,988	6,336	6,221
Product revenue | Asia Pacific
Revenue recognition
Revenue	930	974	2,656	2,271
Instruments
Revenue recognition
Revenue	2,764	2,703	6,452	6,119
Instruments | NA
Revenue recognition
Revenue	1,220	1,159	2,973	2,556
Instruments | EMEA
Revenue recognition
Revenue	1,009	893	1,735	2,038
Instruments | Asia Pacific
Revenue recognition
Revenue	535	651	1,744	1,525
Consumable and other products
Revenue recognition
Revenue	4,026	6,073	10,171	12,204
Consumable and other products | NA
Revenue recognition
Revenue	1,734	3,655	4,658	7,274
Consumable and other products | EMEA
Revenue recognition
Revenue	1,897	2,095	4,601	4,183
Consumable and other products | Asia Pacific
Revenue recognition
Revenue	395	323	912	747
Service and other revenue
Revenue recognition
Revenue	6,317	4,760	12,079	7,550
Service and other revenue | NA
Revenue recognition
Revenue	5,200	3,785	9,846	6,179
Service and other revenue | EMEA
Revenue recognition
Revenue	965	732	1,486	1,074
Service and other revenue | Asia Pacific
Revenue recognition
Revenue	152	243	747	297
Service-type warranties
Revenue recognition
Revenue	1,175	1,142	2,354	2,102
Service-type warranties | NA
Revenue recognition
Revenue	731	814	1,479	1,503
Service-type warranties | EMEA
Revenue recognition
Revenue	385	300	764	534
Service-type warranties | Asia Pacific
Revenue recognition
Revenue	59	28	111	65
Research services
Revenue recognition
Revenue	4,982	3,207	9,269	4,711
Research services | NA
Revenue recognition
Revenue	4,394	2,771	8,061	4,275
Research services | EMEA
Revenue recognition
Revenue	513	223	595	223
Research services | Asia Pacific
Revenue recognition
Revenue	75	213	613	213
Other services
Revenue recognition
Revenue	160	411	456	737
Other services | NA
Revenue recognition
Revenue	75	200	306	401
Other services | EMEA
Revenue recognition
Revenue	67	209	127	317
Other services | Asia Pacific
Revenue recognition
Revenue	18	$ 2	23	$ 19
Collaboration and license revenue
Revenue recognition
Revenue	23		155
Collaboration and license revenue | NA
Revenue recognition
Revenue	22		144
Collaboration and license revenue | EMEA
Revenue recognition
Revenue	$ 1		$ 11