Share based compensation arrangement by share based payment award vesting date.

No definition available.

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- Definition

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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- Definition

Number of common shares reserved for future issuance related to deferred compensation arrangements with individuals.

+ References

No definition available.

+ Details

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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

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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- Definition

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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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

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

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- Definition

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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- Definition

Description of pertinent provisions of equity-based compensation awards that have actual or potential impact upon the company's financial statements.

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- Definition

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

+ References

No definition available.

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- Definition

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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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Share-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance		10,287,390
Weighted average grant date fair value of stock options granted		$ 15.22	$ 15.08	$ 48.85
Total intrinsic value of the options exercised		$ 1,683,679	$ 1,609,268	$ 2,984,283
Total fair value of shares vested		$ 11,348,595	$ 7,212,195	$ 9,310,898
Options granted, Number of Shares		1,175,187
Options granted, exercise price		$ 15.22
Unrecognized share-based compensation expense related to employee stock option awards		$ 13,669,451
Expected dividend yield		0.00%	0.00%	0.00%
Risk free interest rate		2.48%	2.10%	1.70%
Scientific Advisory Board Members [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term		2 years
Options granted, Number of Shares		12,000	0	5,000
Options granted, exercise price		$ 15.47	$ 0.00	$ 53.63
2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance		4,807,323
Total Shareholder Return Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term	3 years
Weighted average grant date fair value of stock options granted	$ 17.08
Unrecognized compensation costs related to unvested RSUs			$ 4,177,362
Unrecognized share-based compensation expense, weighted-average recognition period			1 year
Expected dividend yield	0.00%
Risk free interest rate	1.60%
Expected volatility	95.40%
Vesting date	Dec. 31, 2019
Terms of award		Total shareholder return is determined by dividing the average share value of the Company’s common stock over the 30 trading days preceding January 1, 2020 by the average share value of the Company’s common stock over the 30 trading days beginning on January 1, 2017, with a deemed reinvestment of any dividends declared during the performance period.
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested RSUs		$ 6,493,399	$ 2,866,164
Unrecognized share-based compensation expense, weighted-average recognition period		1 year 10 months 24 days
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock-based compensation expense recognized		$ 4,800,000	$ 2,100,000	$ 1,500,000
Milestone Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested RSUs		$ 2,795,202
Unrecognized share-based compensation expense, weighted-average recognition period		1 year
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, maximum term		10 years
Unrecognized share-based compensation expense, weighted-average recognition period		2 years
Stock Options [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term		1 year
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting term		3 years