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Stockholders' Equity - Schedule of Fair Value of Warrant Valuation Assumptions (Detail) - $ / shares		12 Months Ended
	Apr. 14, 2016	Dec. 31, 2016
Schedule Of Warrant Valuation Assumptions [Line Items]
Price per share of Allenex used to determine fair value of non controlling interest		$ 2.70
Private Placement Warrants [Member]
Schedule Of Warrant Valuation Assumptions [Line Items]
Price per share of Allenex used to determine fair value of non controlling interest	$ 4.45	2.70
Exercise Price	$ 4.98	$ 4.00
Remaining term (in years)	7 years	6 years 3 months 15 days
Volatility	46.90%	51.40%
Risk-free interest rate	1.57%	2.14%
Expected dividend yield	0.00%	0.00%
Placement Agent Warrants [Member]
Schedule Of Warrant Valuation Assumptions [Line Items]
Price per share of Allenex used to determine fair value of non controlling interest	$ 4.45	$ 2.70
Exercise Price	$ 3.99	$ 3.99
Remaining term (in years)	5 years	4 years 3 months 15 days
Volatility	49.00%	56.10%
Risk-free interest rate	1.26%	1.77%
Expected dividend yield	0.00%	0.00%

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Schedule of warrant valuation assumptions.

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- Definition

Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Price of a single share of a number of saleable stocks of a company.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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