Summary of Available-for-Sale Marketable Securities (Detail) - USD ($)
$ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Available-for-sale-matures within one year, Amortized cost |
$ 9,456
|
$ 9,258
|
| Available-for-sale-matures within one year through three years, Amortized cost |
|
39,501
|
| Available-for-sale-matures after one year through three years, Gross unrealized gains |
|
0
|
| Available-for-sale-matures after one year through three years, Gross unrealized losses |
|
(444)
|
| Available-for-sale-matures after one year through three years, Fair value |
|
39,057
|
| Available-for-sale-matures within one year through five years, Amortized cost |
52,991
|
|
| Amortized cost, Total |
62,447
|
48,759
|
| Available-for-sale-matures within one year, Gross unrealized gains |
4
|
1
|
| Available-for-sale-matures after one year through five years, Gross unrealized gains |
3
|
|
| Gross unrealized gains, Total |
7
|
1
|
| Available-for-sale-matures within one year, Gross unrealized losses |
(15)
|
(50)
|
| Available-for-sale-matures after one year through five years, Gross unrealized losses |
(571)
|
|
| Gross unrealized losses, Total |
(586)
|
(494)
|
| Available-for-sale-matures within one year, Fair value |
9,445
|
9,209
|
| Available-for-sale-matures after one year through five years, Fair value |
52,423
|
|
| Fair value, Total |
61,868
|
48,266
|
| Certificates of deposits |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Available-for-sale-matures within one year, Amortized cost |
|
1
|
| Available-for-sale-matures within one year, Fair value |
|
1
|
| Fair value, Total |
|
1
|
| Corporate bonds |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Available-for-sale-matures within one year, Amortized cost |
9,456
|
9,257
|
| Available-for-sale-matures within one year through three years, Amortized cost |
|
39,501
|
| Available-for-sale-matures after one year through three years, Gross unrealized gains |
|
0
|
| Available-for-sale-matures after one year through three years, Gross unrealized losses |
|
(444)
|
| Available-for-sale-matures after one year through three years, Fair value |
|
39,057
|
| Available-for-sale-matures within one year through five years, Amortized cost |
52,490
|
|
| Available-for-sale-matures within one year, Gross unrealized gains |
4
|
1
|
| Available-for-sale-matures after one year through five years, Gross unrealized gains |
3
|
|
| Available-for-sale-matures within one year, Gross unrealized losses |
(15)
|
(50)
|
| Available-for-sale-matures after one year through five years, Gross unrealized losses |
(567)
|
|
| Available-for-sale-matures within one year, Fair value |
9,445
|
$ 9,208
|
| Available-for-sale-matures after one year through five years, Fair value |
51,926
|
|
| Government bonds |
|
|
| Schedule of Available-for-sale Securities [Line Items] |
|
|
| Available-for-sale-matures within one year through five years, Amortized cost |
501
|
|
| Available-for-sale-matures after one year through five years, Gross unrealized losses |
(4)
|
|
| Available-for-sale-matures after one year through five years, Fair value |
497
|
|
| Fair value, Total |
$ 497
|
|