Consolidated Balance Sheet Detail - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Jan. 31, 2018	Apr. 30, 2017	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Balance Sheet Related Disclosures [Line Items]
Depreciation and amortization expense				$ 2,273	$ 2,953	$ 3,380
Loss on impairment of long-lived assets held for sale			$ 300		300
Proceeds from sale of facility held for sale		$ 100
Proceeds from sale of investment in affiliates				4,555		$ 464
Layer3 TV, Inc. [Member]
Balance Sheet Related Disclosures [Line Items]
Proceeds from sale of investment in affiliates	$ 4,600		$ 4,600
Additional payment being held in escrow, related to sale of investment in affiliates	$ 2,100			2,100
Gain (loss) on investment in affiliates				$ 2,600	$ 2,600