Financial Instruments - Additional Information (Detail) - USD ($) |
12 Months Ended | 36 Months Ended | ||||
|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2016 |
Feb. 29, 2016 |
Dec. 31, 2012 |
|
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||||||
| Rent | $ 267,000 | |||||
| Lease expiration period | 2018-03 | |||||
| Aggregate rent expense | $ 465,000 | $ 467,000 | $ 517,000 | |||
| Future annual minimum lease commitments for 2017 | 371,000 | $ 371,000 | ||||
| Future annual minimum lease commitments for 2018 | 86,000 | 86,000 | ||||
| Future annual minimum lease commitments for 2019 | 8,000 | 8,000 | ||||
| Forgivable loan | $ 500,000 | |||||
| Interest on forgivable loan | 4.25% | |||||
| Non current note payable | $ 190,000 | 190,000 | $ 190,000 | |||
| Forgivable loan, expiration date | Mar. 31, 2016 | |||||
| Interest paid | $ 0 | |||||
| Belgium [Member] | ||||||
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||||||
| Rent | $ 172,000 | |||||
| Lease expiration period | 2017-07 | |||||