Stock-Based Compensation - Restricted Stock Units (Details) - USD ($)	9 Months Ended
Sep. 30, 2018
Weighted Average Exercise Price Per Share
Unrecognized stock-based compensation expense	$ 5,500,000
Unrecognized compensation expense, weighted-average period expected to be recognized	2 years 9 months 18 days
RSU
Number of Restricted Stock Units
Balance, beginning of period	30,680
Granted	75,700
Vested	(10,000)
Cancelled/forfeited	(1,900)
Balance, end of period	94,480
Weighted Average Exercise Price Per Share
Balance, beginning of period (price per share)	$ 10.55
Granted (price per share)	8.59
Vested (price per share)	16.25
Cancelled/forfeited	8.39
Balance, end of period (price per share)	$ 8.42
2016 Employee Incentive Plan \| RSU
Weighted Average Exercise Price Per Share
Unrecognized stock-based compensation expense	$ 645,000
Unrecognized compensation expense, weighted-average period expected to be recognized	3 years

Weighted-average exercise price, cancelled or forfeited, for vested other than options outstanding.

No definition available.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the other than stock option plan.

+ References

No definition available.

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- Definition

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No definition available.

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- Definition

Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for vested other than options outstanding.

+ References

No definition available.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of other than options.

+ References

No definition available.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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- Definition

Net number of non-option equity instruments granted to participants.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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