Common Stock - Summary of Outstanding Warrants (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 19, 2018
Class of Warrant or Right [Line Items]
Exercise price per Share			$ 4.00
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	25,272
Exercise price per Share	$ 440.0000
Expiration Date	2019-07
Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	6,093
Exercise price per Share	$ 440.0000
Expiration Date	2019-07
Series A-1 Warrants [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	2,175
Exercise price per Share	$ 264.0000
Expiration Date	2020-10
Warrants Issued In September 2017 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	8,224
Exercise price per Share	$ 34.9600
Expiration Date	2023-03
Warrants Issued In June 2018 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	2,282,000
Exercise price per Share	$ 4.0000	$ 4.00
Expiration Date	2023-06
Warrants Issued in October 2018 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	624,313
Exercise price per Share	$ 3.1445
Expiration Date	2023-10
Warrants Issued in May 2019 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	1,200,000
Exercise price per Share	$ 4.5000
Expiration Date	2025-05