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Subsequent Events - Additional Information (Details) - USD ($)					3 Months Ended
	May 07, 2020	Apr. 23, 2020	Apr. 01, 2020	Mar. 29, 2020	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2019	Apr. 30, 2020	Dec. 31, 2019	Aug. 06, 2019	Aug. 05, 2019	May 29, 2015
Subsequent Event [Line Items]
Warrant liability						$ 5,262,000			$ 6,929,000
Change in fair value of warrants						$ (1,667,000)	$ (210,000)
Common stock, shares issued (in shares)						3,880,588			3,880,588	50,000,000	50,000,000
NanoTx License Agreement [Member]
Subsequent Event [Line Items]
License fee payment in cash				$ 400,000
Term Loan [Member]
Subsequent Event [Line Items]
Number of shares callable by warrants (in shares)												188
Warrant exercise price (in dollars per share)												$ 5,175
Scenario Forecast [Member]
Subsequent Event [Line Items]
Change in fair value of warrants					$ 700,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Warrant liability								$ 4,200,000
Subsequent Event [Member] | NanoTx License Agreement [Member]
Subsequent Event [Line Items]
License agreement expiration date	May 07, 2020
License fee payment in cash	$ 400,000
Common stock, shares issued (in shares)	230,769
Subsequent Event [Member] | Term Loan [Member]
Subsequent Event [Line Items]
Repayment of debt			$ 5,000,000
Final payment fee			$ 308,000
Subsequent Event [Member] | Revised Warrant Agreements [Member] | Series T Warrants [Member]
Subsequent Event [Line Items]
Number of shares callable by warrants (in shares)		1
Series U Warrants [Member] | Subsequent Event [Member] | Revised Warrant Agreements [Member]
Subsequent Event [Line Items]
Number of warrants		3,372,000
Warrant exercise price decrease		$ 2.25
Outstanding Warrants [Member] | Subsequent Event [Member] | Revised Warrant Agreements [Member] | Series T Warrants [Member]
Subsequent Event [Line Items]
Number of shares callable by warrants (in shares)		50
Warrant exercise price (in dollars per share)		$ 2.25

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