Quarterly report pursuant to Section 13 or 15(d)

Other Current Liabilities (Details)

v3.10.0.1
Other Current Liabilities (Details)
$ in Millions
3 Months Ended
Jun. 30, 2018
USD ($)
kW
Jun. 30, 2017
USD ($)
Mar. 31, 2018
USD ($)
C200      
Other Current Liabilities      
Capacity of microturbine (in kW) | kW 200    
Carrier      
Other Current Liabilities      
Royalties earned $ 0.3 $ 0.2  
Unpaid earned royalties $ 0.3   $ 0.2