Stockholders' Equity - Summary of Outstanding Warrants (Detail) - $ / shares				9 Months Ended
	Oct. 10, 2019	May 23, 2019	Jul. 30, 2018	Sep. 26, 2020	Mar. 07, 2018
(1) Warrants related to October 2015 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				13,552
Common Shares, Currently Exercisable				13,552
Common Shares, Price per Share				$ 600.00
Common Shares, Expiration Date				Oct. 14, 2020
(2)  Warrants related to October 2015 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				903
Common Shares, Currently Exercisable				903
Common Shares, Price per Share				$ 656.30
Common Shares, Expiration Date				Oct. 14, 2020
(3)  Warrants related to August 2016 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				5,350
Common Shares, Currently Exercisable				5,350
Common Shares, Price per Share				$ 300.00
Common Shares, Expiration Date				Feb. 02, 2022
(4)  Warrants related to August 2016 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				500
Common Shares, Currently Exercisable				500
Common Shares, Price per Share				$ 385.50
Common Shares, Expiration Date				Aug. 02, 2021
(5)  Warrants related to December 2016 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				68,567
Common Shares, Currently Exercisable				68,567
Common Shares, Price per Share				$ 200.00
Common Shares, Expiration Date				Dec. 14, 2021
(6) Warrants related to March 2018 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				15,810
Common Shares, Currently Exercisable				15,810
Common Shares, Price per Share				$ 114.00
Common Shares, Expiration Date				Sep. 09, 2023
(7)  Warrants related to March 2018 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding				1,107
Common Shares, Currently Exercisable				1,107
Common Shares, Price per Share				$ 158.00
Common Shares, Expiration Date				Mar. 06, 2023
(8) Warrants related to July 2018 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding			257,142	257,143
Common Shares, Currently Exercisable				257,143
Common Shares, Price per Share			$ 35.00	$ 35.00
Common Shares, Expiration Date			Jul. 25, 2023	Jul. 25, 2023
(9)  Warrants related to July 2018 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding			15,428	15,428
Common Shares, Currently Exercisable				15,428
Common Shares, Price per Share			$ 43.75	$ 43.75	$ 114.00
Common Shares, Expiration Date				Jul. 25, 2023
(10)  Warrants related to May 2019 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding		170,000		11,900
Common Shares, Currently Exercisable				11,900
Common Shares, Price per Share		$ 12.50		$ 12.50
Common Shares, Expiration Date		May 23, 2024		May 23, 2024
(11)  Warrants related to October 2019 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding	1,183,400			217,200
Common Shares, Currently Exercisable				217,200
Common Shares, Price per Share	$ 2.50			$ 2.50
Common Shares, Expiration Date				Oct. 10, 2024
(12)   Warrants related to October 2019 financing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding	82,838			30,916
Common Shares, Currently Exercisable				30,916
Common Shares, Price per Share	$ 3.125			$ 3.13
Common Shares, Expiration Date	Oct. 08, 2024			Oct. 08, 2024