Stockholders' Equity - Additional Information (Detail) - USD ($)			1 Months Ended
	May 26, 2017	May 10, 2017	May 26, 2017	Jan. 27, 2017
Class of Stock [Line Items]
Proceeds from additional equity offering		$ 17,000,000	$ 17,000,000
Public stock offering
Class of Stock [Line Items]
Common stock, shares issued (in shares)		4,000,000
Sale of stock, price per share (in dollars per share)		$ 4.00
Proceeds from additional equity offering		$ 14,700,000
Over-allotment option
Class of Stock [Line Items]
Common stock, shares issued (in shares)		600,000
Proceeds from additional equity offering	$ 2,300,000
Over allotment common stock options period (in shares)		30 days
ATM issuance sales agreement
Class of Stock [Line Items]
Maximum value of shares for sale				$ 10,000,000.0