Business Combinations - Contingent Consideration (Details) - USD ($) $ in Thousands	Apr. 04, 2018	Jan. 16, 2018	Jun. 30, 2018	Dec. 31, 2017
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration			$ 178,449	$ 33,973
ImThera Medical, Inc.
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration		$ 112,744
ImThera Medical, Inc. \| Discounted Cash Flow
Business Acquisition, Contingent Consideration [Line Items]
Regulatory milestone-based payment		$ 50,429
ImThera Medical, Inc. \| Discounted Cash Flow \| Minimum
Business Acquisition, Contingent Consideration [Line Items]
Discount rate		4.30%
Probability of payment		85.00%
ImThera Medical, Inc. \| Discounted Cash Flow \| Maximum
Business Acquisition, Contingent Consideration [Line Items]
Discount rate		4.70%
Probability of payment		95.00%
ImThera Medical, Inc. \| Monte Carlo Simulation
Business Acquisition, Contingent Consideration [Line Items]
Sales-based earnout		$ 62,315
Risk adjusted discount rate		11.50%
Revenue volatility		29.30%
ImThera Medical, Inc. \| Monte Carlo Simulation \| Minimum
Business Acquisition, Contingent Consideration [Line Items]
Probability of payment		85.00%
Credit risk rate		5.00%
ImThera Medical, Inc. \| Monte Carlo Simulation \| Maximum
Business Acquisition, Contingent Consideration [Line Items]
Probability of payment		95.00%
Credit risk rate		6.00%
TandemLife
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration	$ 50,000
TandemLife \| Discounted Cash Flow
Business Acquisition, Contingent Consideration [Line Items]
Regulatory milestone-based payment	$ 40,190
TandemLife \| Discounted Cash Flow \| Minimum
Business Acquisition, Contingent Consideration [Line Items]
Discount rate	4.20%
Probability of payment	75.00%
TandemLife \| Discounted Cash Flow \| Maximum
Business Acquisition, Contingent Consideration [Line Items]
Discount rate	4.80%
Probability of payment	95.00%