Stock-Based Compensation - Additional Information (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2018 USD ($) shares	Jun. 30, 2018 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued as result of option exercises		702,735
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting Period		4 years
Stock option expiration Period		10 years
Unrecognized compensation cost, stock options \| $	$ 1,204,432	$ 1,204,432
Unrecognized stock-based compensation expense, period for recognition		2 years 6 months
Common stock issued as result of option exercises	55,120	286,218
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense, period for recognition		2 years 3 months 19 days
Unrecognized compensation expense \| $	$ 3,230	$ 3,230
Unvested restricted stock, shares	19,168	19,168
Common stock issued as result of vesting of restricted stock	2,130	4,260

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 share-based awards, other than options, awarded to employees as compensation.

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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 non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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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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Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

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Number of share options (or share units) exercised during the current period.

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