Common Stock Reserved for Future Issuance (Details) - shares	Mar. 31, 2020	Dec. 31, 2019
Common Stock
Shares reserved for future issuance (in shares)	7,653,455	7,617,546
Common stock warrants
Common Stock
Shares reserved for future issuance (in shares)	6,193,749	6,193,749
Common stock options outstanding
Common Stock
Shares reserved for future issuance (in shares)	1,206,644	785,832
Common stock options available for future issuance
Common Stock
Shares reserved for future issuance (in shares)	104,111	525,484
Employee stock purchase plan
Common Stock
Shares reserved for future issuance (in shares)	148,951	112,481