Warrants - Summary of Warrants Outstanding (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Warrant or Right [Line Items]
Warrants Outstanding	4,796,621	175,584	175,584
Exercise Price 1.50 [Member]
Class of Warrant or Right [Line Items]
Exercise Price	$ 1.50
Warrants Outstanding	175,584
Expiration Date	Jul. 31, 2017
Exercise Price 0.31 [Member]
Class of Warrant or Right [Line Items]
Exercise Price	$ 0.31
Warrants Outstanding	4,621,037
Expiration Date	May 10, 2024