Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands			12 Months Ended
	Aug. 02, 2019	Aug. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same amounts shown in the statement of cash flows:
Cash and cash equivalents			$ 54,437	$ 54,062	$ 41,538
Restricted cash			1,764	6,614	1,614
Total cash, cash equivalents and restricted cash as shown on the statement of cash flow			56,201	60,676	$ 43,152	$ 34,664
Credit Agreement
Restricted Cash
Total indebtedness			25,000	25,000
Minimum cash in hand as a financial covenant	$ 5,000	$ 5,000	5,000
Security deposit
Reconciliation of the cash, cash equivalents, and restricted cash reported within the balance sheet that sum to the total of the same amounts shown in the statement of cash flows:
Restricted cash			$ 1,764	$ 6,614