Summary of significant accounting policies - Segment and geographic information (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)
Primary revenue source
Number of reportable segment \| segment			1
Revenue	$ 58,672	$ 68,554	$ 118,558	$ 135,027
Military/multifamily
Primary revenue source
Revenue	23,713	24,396	46,420	50,293
DAS
Primary revenue source
Revenue	22,214	27,622	44,410	51,717
Wholesale-Wi-Fi
Primary revenue source
Revenue	9,706	10,718	19,449	21,738
Retail
Primary revenue source
Revenue	2,368	3,847	5,327	7,773
Advertising and other
Primary revenue source
Revenue	$ 671	$ 1,971	$ 2,952	$ 3,506

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

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Balance Type:	credit
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