Acquisitions - Purchase Price Allocation (Argon Medical Devices, Inc.) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Jan. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Gain on bargain purchase		$ 778		$ 0	$ (10,796)	$ 0
Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents		1,436			1,436
Trade receivables		8,351			8,351
Inventories		11,222			11,222
Prepaid expenses		1,275			1,275
Property and equipment		2,319			2,319
Deferred tax assets		203			203
Total assets acquired		29,406			29,406
Trade payables		(2,415)			(2,415)
Accrued expenses		(5,083)			(5,083)
Income taxes payable		(2)			(2)
Deferred income tax liabilities - noncurrent		(1,010)			(1,010)
Total liabilities assumed		(8,510)			(8,510)
Total net assets acquired		20,896			20,896
Gain on bargain purchase					(10,796)
Total purchase price	$ 10,100
Provisional gain on bargain purchase		778	$ 669
Preliminary Allocation | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents		1,436			1,436
Trade receivables		8,351			8,351
Inventories		12,217			12,217
Prepaid expenses		1,275			1,275
Property and equipment		2,667			2,667
Deferred tax assets		184			184
Total assets acquired		31,530			31,530
Trade payables		(2,306)			(2,306)
Accrued expenses		(5,083)			(5,083)
Income taxes payable		(2)			(2)
Deferred income tax liabilities - noncurrent		(999)			(999)
Total liabilities assumed		(8,390)			(8,390)
Total net assets acquired		23,140			23,140
Gain on bargain purchase					(12,243)
Total purchase price	10,897
Adjustment | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents		0			0
Trade receivables		0			0
Inventories		(995)			(995)
Prepaid expenses		0			0
Property and equipment		(348)			(348)
Deferred tax assets		19			19
Total assets acquired		(2,124)			(2,124)
Trade payables		(109)			(109)
Accrued expenses		0			0
Income taxes payable		0			0
Deferred income tax liabilities - noncurrent		(11)			(11)
Total liabilities assumed		(120)			(120)
Total net assets acquired		(2,244)			(2,244)
Gain on bargain purchase					1,447
Total purchase price	$ (797)
Developed Technology Rights | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		2,200			2,200
Developed Technology Rights | Preliminary Allocation | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		2,600			2,600
Developed Technology Rights | Adjustment | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		(400)			(400)
Customer lists | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		1,500			1,500
Customer lists | Preliminary Allocation | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		1,300			1,300
Customer lists | Adjustment | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		200			200
Trademarks | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		900			900
Trademarks | Preliminary Allocation | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		1,500			1,500
Trademarks | Adjustment | Argon Medical Devices, Inc.
Business Acquisition [Line Items]
Intangibles		$ (600)			$ (600)