Exhibit A

AGREEMENT REGARDING THE JOINT FILING OF

SCHEDULE 13G

The undersigned, being duly authorized thereunto, hereby execute this agreement as an exhibit to this Schedule 13G to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule and all amendments thereto jointly on behalf of each such party.

Date: February 11, 2019

TECHNOLOGY PARTNERS FUND VII, L.P.
By:	TP Management VII, LLC
By:	/s/ Sheila Mutter
	Managing Member
TECHNOLOGY PARTNERS AFFILIATES VII, L.P.
By:	TP Management VII, LLC
By:	/s/ Sheila Mutter
	Managing Member
TP MANAGEMENT VII, LLC
By:	/s/ Sheila Mutter
	Managing Member
JAMES GLASHEEN
By:	/s/ James Glasheen
	James Glasheen
SHEILA MUTTER
By:	/s/ Sheila Mutter
	Sheila Mutter
ROGER QUY
By:	/s/ Roger Quy
	Roger Quy
IRA EHRENPREIS
By:	/s/ Ira Ehrenpreis
	Ira Ehrenpreis
TED ARDELL
By:	/s/ Ted Ardell
	Ted Ardell