Business combinations (Details) - USD ($) $ in Thousands			3 Months Ended								12 Months Ended
	Aug. 01, 2019	Jan. 30, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 01, 2019
Fair value of consideration transferred:
Purchase price, net											$ 14,529	$ 3,801
Assets (liabilities) acquired:
Goodwill			$ 9,353				$ 1,308				9,353	1,308
Revenue			15,917	$ 14,944	$ 13,536	$ 12,337	10,877	$ 10,591	$ 8,643	$ 7,521	56,734	37,632	$ 22,874
Net income			$ (10,958)	$ (9,870)	$ (10,563)	$ (9,405)	$ (9,334)	$ (7,657)	$ (7,343)	$ (7,202)	(40,796)	(31,536)	$ (27,019)
Revenue (unaudited)											57,597	38,753
Pre-tax loss (unaudited)											(38,636)	(33,894)
Aushon acquisition
Fair value of consideration transferred:
Cash		$ 3,200
Obligation to issue cash		800
Cash and cash equivalents acquired		199
Purchase price, net		4,000
Assets (liabilities) acquired:
Accounts receivable		210
Inventory		828
Prepaids and other current assets		71
Property and equipment and other non-current assets		180
Intangibles		2,950
Goodwill		1,308
Total assets acquired		5,746
Contractual obligations		(1,155)
Accounts payable and accrued liabilities		(591)
Total		$ 4,000
Risk-adjusted discount rate used to determine fair value of intangible assets		14.40%
Transaction costs												$ 100
UmanDiagnostics AB Acquisition
Fair value of consideration transferred:
Cash	$ 15,700
Common stock shares consideration	191,152
Common stock	$ 5,500
Capital stock shares outstanding, percent	95.00%													5.00%
Cash and stock paid	$ 21,217
Cash and cash equivalents acquired	1,221
Purchase price, net	19,996
Assets (liabilities) acquired:
Accounts receivable	638
Inventory	1,680
Prepaids and other current assets	114
Property and equipment	33
Intangibles	13,450
Goodwill	8,111
Accounts payable	(20)
Accrued expense and other current liabilities	(871)
Deferred tax liabilities	(3,139)
Total	$ 19,996
Revenue											1,100
Net income											100
Transaction costs											$ 1,900