Equity Financings and Warrants - Summary of Warrants by Year of Expiration (Details)	3 Months Ended
	Mar. 31, 2019 $ / shares shares
Class Of Warrant Or Right [Line Items]
Number of Warrants | shares	135,862
Weighted Average Exercise Price | $ / shares	$ 113.04
2020
Class Of Warrant Or Right [Line Items]
Year of Expiration	2020
Number of Warrants | shares	2,461
Weighted Average Exercise Price | $ / shares	$ 287.28
2022
Class Of Warrant Or Right [Line Items]
Year of Expiration	2022
Number of Warrants | shares	133,401
Weighted Average Exercise Price | $ / shares	$ 109.80