Intangible Assets and Goodwill - Additional Information (Detail) - USD ($) |
6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Goodwill And Intangible Assets Disclosure [Abstract] | ||||
| Intangible assets and goodwill impairment | $ 0 | |||
| Goodwill | $ 2,926,000 | $ 2,926,000 | ||
| Amortization expense | $ 0 | $ 51,000 | $ 63,000 | |
| X | ||||||||||
- 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill. No definition available.
|
| X | ||||||||||
- References No definition available.
|