Summary of Impact of Adoption of ASC 606 to Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Contract assets	$ 3,750
Current liabilities:
Deferred revenue	20,043	$ 14,574
Income taxes payable	1,168
Stockholders’ equity:
Retained earnings	262,840	238,953
Accounting Standards Update 2014-09 \| Balances without adoption of ASC 606
Current liabilities:
Deferred revenue	20,000
Stockholders’ equity:
Retained earnings	259,551	241,167
Accounting Standards Update 2014-09 \| Impact of Adoption of ASC 606
Assets:
Contract assets	3,750
Current liabilities:
Deferred revenue	43
Income taxes payable	1,168
Stockholders’ equity:
Retained earnings	$ 3,289	$ 2,214

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130531-203044

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130533-203044

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