Deferred Warranty Revenue and Warranty Reserve - Deferred Warranty Revenue (Details) - Deferred warranty revenue $ in Thousands	Dec. 31, 2017 USD ($)
Deferred revenue, recognition by year
2018	$ 12
2019	3
Total	$ 15

Minimum amount of other commitment maturing in the next fiscal year following the latest fiscal year for commitments not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in this taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitmentDueInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant