Commitments and Contingencies - Additional Information (Detail) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($) ft²	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Restructuring reserve		$ 163		$ 196
Rent expense under leases		200	$ 300
Operating lease obligation		3,208
Allowance for product returns		200		200
Warranty reserve		$ 420		394
Antenna [Member]
Commitments And Contingencies Disclosure [Line Items]
Repair and replacement warranty		5 years
Warranty Reserves [Member]
Commitments And Contingencies Disclosure [Line Items]
Warranty reserve		$ 420	$ 326	394	$ 348
Colorado Office [Member]
Commitments And Contingencies Disclosure [Line Items]
Lease expiration date		Oct. 31, 2020
Operating lease obligation		$ 400
Beijing Design Center [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease obligation	$ 400
Lease term	4 years
Area of office space | ft²	11,270
Accrued Liabilities [Member]
Commitments And Contingencies Disclosure [Line Items]
Restructuring reserve		100		100
Long-term Liabilities [Member]
Commitments And Contingencies Disclosure [Line Items]
Restructuring reserve		$ 100		$ 100