Summary of Significant Accounting Policies - Goodwill and Other Intangibles (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) segment	Sep. 30, 2018 USD ($) segment
Goodwill and Other Intangibles
Number of reporting units | segment	1	1
Goodwill impairment | $	$ 0	$ 0
Patents [Member]
Goodwill and Other Intangibles
Estimated useful lives of assets		20 years
Minimum | Proprietary Technology [Member]
Goodwill and Other Intangibles
Estimated useful lives of assets		3 years
Minimum | Customer Relationships
Goodwill and Other Intangibles
Estimated useful lives of assets		5 years
Maximum | Proprietary Technology [Member]
Goodwill and Other Intangibles
Estimated useful lives of assets		7 years
Maximum | Customer Relationships
Goodwill and Other Intangibles
Estimated useful lives of assets		12 years