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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Accounting Policies - Schedule of Revenues on Disaggregated Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenues	$ 6,525	$ 5,804	$ 18,933	$ 17,242
Wireless [Member]
Disaggregation Of Revenue [Line Items]
Revenues	6,283	4,690	17,605	13,678
Wireless [Member] \| Software [Member]
Disaggregation Of Revenue [Line Items]
Revenues	48	193	311	264
Wireless [Member] \| Platform [Member]
Disaggregation Of Revenue [Line Items]
Revenues	5,908	3,603	15,780	10,858
Wireless [Member] \| Services [Member]
Disaggregation Of Revenue [Line Items]
Revenues	339	593	1,406	1,954
Wireless [Member] \| Contract [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(12)	301	108	602
Graphics [Member]
Disaggregation Of Revenue [Line Items]
Revenues	242	1,114	1,328	3,564
Graphics [Member] \| Software [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 242	$ 1,114	$ 1,328	$ 3,564