Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 80,265	$ 74,179	$ 73,484	$ 69,963	$ 64,435	$ 60,873	$ 59,130	$ 59,906	$ 297,891	$ 244,344	$ 207,869
Subscription and support
Disaggregation of Revenue [Line Items]
Total revenue	$ 66,148	$ 63,022	$ 60,472	$ 56,123	$ 53,779	$ 51,306	$ 48,837	$ 46,470	245,765	200,392	$ 169,283
XBRL professional services
Disaggregation of Revenue [Line Items]
Total revenue									38,734	30,562
Other services
Disaggregation of Revenue [Line Items]
Total revenue									13,392	13,390
Information technology
Disaggregation of Revenue [Line Items]
Total revenue									39,417	31,063
Consumer discretionary
Disaggregation of Revenue [Line Items]
Total revenue									33,658	28,325
Industrials
Disaggregation of Revenue [Line Items]
Total revenue									33,281	28,023
Diversified financials
Disaggregation of Revenue [Line Items]
Total revenue									33,783	27,335
Banks
Disaggregation of Revenue [Line Items]
Total revenue									28,788	23,818
Healthcare
Disaggregation of Revenue [Line Items]
Total revenue									28,100	21,672
Energy
Disaggregation of Revenue [Line Items]
Total revenue									22,551	19,617
Other
Disaggregation of Revenue [Line Items]
Total revenue									$ 78,313	$ 64,491