Subsequent Events (Details) - USD ($) $ in Millions	Feb. 05, 2020	Jan. 28, 2020	Nov. 06, 2018
LIBOR
Subsequent Events
Spread			2.00%
Wells Fargo Bank
Subsequent Events
Maximum borrowing capacity			$ 10
Subsequent Event | Wells Fargo Bank
Subsequent Events
Maximum borrowing capacity	$ 7
Subsequent Event | Wells Fargo Bank | LIBOR
Subsequent Events
Spread	2.50%
Subsequent Event | Sumitomo Electric Industries | Formal cross license and covenant agreement
Subsequent Events
Aggregate fixed cost		$ 2
Installment Payable Period		10 years