Accrued Expenses and Other Liabilities - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accrued Expenses and Other Liabilities
Accrued payroll and related items	$ 4,276	$ 4,252
Artist payables	4,441	4,999
Accrued product costs	1,636	1,914
Accrued marketing	1,121	1,301
Contingent liabilities	1,038	1,176
Accrued post-combination consideration	1,314
Other	5,307	3,540
Accrued expenses and other current liabilities	$ 19,133	$ 17,182