Segment Information (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Revenue, Major Customer [Line Items]
Revenue	$ 36,871	$ 35,401	$ 34,039	$ 33,549	$ 32,947	$ 31,769	$ 30,347	$ 27,922	$ 139,860	$ 122,985	$ 121,768
Customer Member | Accounts Receivable [Member]
Revenue, Major Customer [Line Items]
Accounts receivables and unbilled accounts receivable	9,508				5,240				$ 9,508	$ 5,240	$ 697
Percentage of combined revenue									27.30%	18.00%	3.40%
Customer Member | Sales Revenue, Net [Member]
Revenue, Major Customer [Line Items]
Revenue									$ 17,298	$ 11,070	$ 9,106
Percentage of combined revenue									12.40%	9.00%	7.50%
Customer B [Member] | Accounts Receivable [Member]
Revenue, Major Customer [Line Items]
Accounts receivables and unbilled accounts receivable	$ 758				$ 1,000				$ 758	$ 1,000	$ 243
Percentage of combined revenue									2.20%	3.40%	1.20%
Customer B [Member] | Sales Revenue, Net [Member]
Revenue, Major Customer [Line Items]
Revenue									$ 6,539	$ 6,623	$ 6,511
Percentage of combined revenue									4.70%	5.40%	5.30%