Common Stock - Narrative (Details) - USD ($)			3 Months Ended		12 Months Ended
	Feb. 26, 2020	Jul. 02, 2015	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Mar. 04, 2020	May 23, 2019	May 22, 2019
Class of Stock [Line Items]
Sale of common stock			$ 3,000,000	$ 0
Common stock authorized (shares)			101,250,000		101,250,000		101,250,000	67,500,000
Cowen | At-the-market sale facility
Class of Stock [Line Items]
Compensation payable, percentage of gross sales price		3.00%
Shares of common stock sold (shares)			0		420,796
Sale of common stock					$ 6,200,000
Aspire Capital Fund, LLC
Class of Stock [Line Items]
Sale of common stock	$ 3,000,000
Common stock issued (shares)	2,693,965
JonesTrading Institutional Services LLC
Class of Stock [Line Items]
Compensation fee (percent of gross proceeds)						3.00%
Maximum | Cowen | At-the-market sale facility
Class of Stock [Line Items]
Planned proceeds from sale of stock (up to)		$ 30,000,000
Common Stock | Aspire Capital Fund, LLC
Class of Stock [Line Items]
Authorized amount of stock repurchase	$ 30,000,000
Remaining authorized stock purchase amount	$ 27,000,000
Purchase period (months)	30 months
Commitment fee (shares)	646,551
Common Stock | JonesTrading Institutional Services LLC
Class of Stock [Line Items]
Shares of common stock sold (shares)			0
Authorized amount						$ 30,000,000