Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) - Customer	3 Months Ended	12 Months Ended
	Mar. 31, 2020 customer	Dec. 31, 2019 customer USD ($)
Total revenue
Concentration risk
Number of major customers	3	2
Total revenue | Customer one
Concentration risk
Concentration risk	36.00%	27.00%
Total revenue | Customer two
Concentration risk
Concentration risk	22.00%	11.00%
Total revenue | Customer three
Concentration risk
Concentration risk	13.00%
Accounts receivable
Concentration risk
Number of major customers	3	3
Accounts receivable | Customer one
Concentration risk
Concentration risk	46.00%	39.00%
Accounts receivable | Customer two
Concentration risk
Concentration risk	21.00%	18.00%
Accounts receivable | Customer three
Concentration risk
Concentration risk	16.00%	11.00%