Balance Sheet - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jul. 31, 2016 USD ($) Customer	Jan. 31, 2016 USD ($) Customer	Dec. 31, 2015 USD ($)
Balance Sheet [Line Items]
Contracts receivable	$ 2,753,000	$ 2,877,000
Number of customers due | Customer	3	3
Contracts receivable, interest rate	2.20%	2.40%
Number of customers entered into structured payment arrangements | Customer	4
Long-term accounts receivable with two customers	$ 3,700,000
Number of customers with long-term accounts receivable | Customer	2
Long-term contracts receivable with two customers	$ 1,300,000
Number of customers with long-term contracts receivable | Customer	2
Impairment charges related to long-lived assets		$ 0
Klein Associates Inc. [Member]
Balance Sheet [Line Items]
Inventory acquired			$ 3,300,000
Minimum [Member]
Balance Sheet [Line Items]
Contracts receivable repayment term	1 month	1 month
Maximum [Member]
Balance Sheet [Line Items]
Contracts receivable repayment term	40 months	40 months