Warrants - Summary of Assumptions to Use Option Pricing Model (Detail)		1 Months Ended	6 Months Ended	12 Months Ended
Aug. 22, 2016	Jan. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
2016 Placement Warrant
Fair Value Inputs Liabilities Quantitative Information [Line Items]
Expected term (in years)	7 years		6 years 2 months 12 days	6 years 8 months 12 days
Expected volatility	61.60%		65.80%	63.60%
Risk-free interest rate	1.40%		2.00%	2.30%
Expected dividend yield	0.00%		0.00%	0.00%
2017 Placement Warrant
Fair Value Inputs Liabilities Quantitative Information [Line Items]
Expected term (in years)		7 years	6 years 7 months 6 days
Expected volatility		62.90%	65.90%
Risk-free interest rate		2.20%	2.00%
Expected dividend yield		0.00%	0.00%

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Risk-free interest rate assumption used in valuing an instrument.

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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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