Stockholders' Equity and Equity Compensation - Financial Data for Stock Option Exercises (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Equity [Abstract]
Aggregate intrinsic value of outstanding stock options	$ 403	$ 349
Aggregate intrinsic value of exercisable stock options	$ 403	$ 349

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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