Summary of Significant Accounting Policies - Costs (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of Significant Accounting Policies
Advertising costs	$ 0.5	$ 0.4	$ 1.1
Shipping and handling costs	9.5	8.2	7.0
Capitalized software	2.6	1.3
Amortized expense	$ 1.0	$ 0.6	$ 0.2

No definition available.

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- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 720
-SubTopic 35
-Section 50
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- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The carrying amount of capitalized computer software costs net of accumulated amortization as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Cost incurred during the reporting period in transporting goods and services to customers. Includes freight-out costs.

+ References

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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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