Revenue, Deferred Revenue and Deferred Contract Costs - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 308,653	$ 258,438	$ 596,484	$ 508,212
Subscription service revenue
Disaggregation of Revenue [Line Items]
Total revenue	286,705	244,137	557,646	480,858
Subscription software revenue
Disaggregation of Revenue [Line Items]
Total revenue	16,805	10,755	29,476	18,103
Hardware and Service
Disaggregation of Revenue [Line Items]
Total revenue	$ 5,143	$ 3,546	$ 9,362	$ 9,251

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

PROOFPOINT INC 10-Q