Accounts Payable and Other Accrued Expenses - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended
	Jan. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Short-term Debt [Line Items]
Restitution payment accrual related to trailing fees			$ 319	$ 739
Soft dollar accruals			1,188	704
Accrued professional fees			119
Financial obligation			595
Accrued fixed assets payable			380
Accrued rent, other			396
Clearing fees			228
Recruiting fee payable				187
Sales and use tax accrual				$ 189
Annual Subscription Fee
Short-term Debt [Line Items]
Financial obligation			308
System Implementation
Short-term Debt [Line Items]
Financial obligation			$ 650
Product Financing Arrangement | Annual Subscription Fee
Short-term Debt [Line Items]
Debt instrument, term		12 months
Product Financing Arrangement | System Implementation
Short-term Debt [Line Items]
Debt instrument, term	36 months