Revenue - Summary of Revenues by Revenue Stream (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue Recognition [Line Items]
Revenues	$ 90,094	$ 74,192
Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	82,801	70,038
One-time Revenues [Member]
Revenue Recognition [Line Items]
Revenues	7,293	4,154
Fulfillment [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	71,404	59,103
Analytics [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	10,144	9,736
Other [Member] | Recurring Revenues [Member]
Revenue Recognition [Line Items]
Revenues	$ 1,253	$ 1,199