Summary of Significant Accounting Policies - Research and Development (Details 6) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Research and Development
Recovery of Direct Costs	$ 4,483	$ 4,299
Other Current Assets
Research and Development
Cost of molds, dies and other tools included in other current assets	$ 5,388	$ 3,382

Carrying amount as of the balance sheet date of capitalized costs of molds, dies, and other tools that will be used in producing products under a long-term supply arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6387057&loc=d3e6169-108318

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=27011391&loc=d3e105117-122735

Name:	us-gaap_PreproductionCostsRelatedToLongTermSupplyArrangementsAssetForMoldsDiesAndToolsOwned
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant