CAPITAL STOCK - Reserved Authorized Shares of Common Stock (Details)	Sep. 30, 2019 shares
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	3,571,692
Common stock options outstanding
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	1,802,895
Common stock warrants
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	1,632,495
Vical Plan | Options available for grant under the 2009 Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	119,070
2009 Plan | Options available for grant under the 2009 Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	17,232