Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental disclosure of cash flow activities:
Cash paid for income taxes	$ 55	$ 93	$ 416
Cash paid for operating leases subject to ASU 842	6,866
Cash paid for interest expense	0	0	101
Supplemental disclosure of non-cash investing and financing activities:
Common stock issued for settlement of restricted stock unit awards	1,391	1,312	3,206
Purchase of property and equipment in accounts payable and accrued expenses	116	6	13
Cash holdback related to acquisition	0	472	0
Deferred tax liability related to acquisition	0	1,015	0
Contingent consideration on acquisition	$ 0	$ 1,500	$ 0