Revenue - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Trade receivables	$ 5,496	$ 6,425
Unbilled receivables	1,886	1,857
Other short-term receivables	33	7
Allowance for doubtful accounts	(1,795)	(1,816)
Total accounts receivable	$ 5,620	$ 6,473