Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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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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Unrecognized cost of unvested options awarded to employees as compensation.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Purchase price of common stock expressed as a percentage of its fair value.

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Stock-based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2013	Dec. 31, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation expense	$ 339,000	$ 194,000	$ 716,000	$ 440,000
2005 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation shares authorized under stock option plans	770,000		770,000
Percent of the fair value options granted			100.00%
Stock options granted			0	0
Shares available for grant	0		0
Weighted average remaining contractual term stock options outstanding			2 years 7 months 17 days
Weighted average remaining contractual life for options exercisable			2 years 7 months 17 days
2005 Plan \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			5 years
Stock options, when granted, expiration period			10 years
2010 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation shares authorized under stock option plans	87,427		87,427		2,500,000	1,350,000
Percent of the fair value options granted			100.00%
Stock options granted			0	0
Weighted average remaining contractual term stock options outstanding			2 years 10 months 2 days
Weighted average remaining contractual life for options exercisable			2 years 6 months 18 days
Unrecognized compensation costs related to unvested stock options	$ 2,300,000		$ 2,300,000
Unrecognized compensation costs weighted average period			1 year 3 months 29 days
2010 Plan \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			5 years
Stock options, when granted, expiration period			10 years
2010 Plan \| Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years	3 years
Restricted stock awards granted			3,000	148,000
Weighted average fair value of Restricted shares granted			$ 8.15	$ 12.7