Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,478	$ 85,592
Accumulated Amortization	(81,017)	(72,775)
Total future amortization expense	$ 4,461	12,817
Developed core technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 months 12 days
Gross Carrying Amount	$ 31,707	31,707
Accumulated Amortization	(30,757)	(25,576)
Total future amortization expense	$ 950	6,131
Customer relationships/contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year 2 months 12 days
Gross Carrying Amount	$ 44,577	44,650
Accumulated Amortization	(41,092)	(38,146)
Total future amortization expense	$ 3,485	6,504
Trademarks and tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 months 12 days
Gross Carrying Amount	$ 609	623
Accumulated Amortization	(583)	(441)
Total future amortization expense	26	182
Maintenance agreements and related relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,500	5,500
Accumulated Amortization	(5,500)	(5,500)
Total future amortization expense	0	0
Order or Production Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,085	3,112
Accumulated Amortization	(3,085)	(3,112)
Total future amortization expense	$ 0	$ 0