XML 34 R21.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Marketable Securities (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2017
Marketable Securities |
Summary of marketable securities, classified as available-for-sale |
|  | Amortized Cost |  | Gross Unrealized Gains |  | Gross Unrealized Losses |  | Fair Value |
|  | (In thousands) |
June 30, 2017 |  |  |  |  |  |  |  |  |
Marketable securities |  |  |  |  |  |  |  |  |
U.S. government and municipal obligations |  |  |  |  |  |  |  |  |
Maturing in one year or less |  | $ | 18,253 |  | $ | 7 |  | $ | (6 | ) | $ | 18,254 |
Maturing after one year through three years |  | — |  | — |  | — |  | — |
Total U.S. government and municipal obligations |  | $ | 18,253 |  | $ | 7 |  | $ | (6 | ) | $ | 18,254 |
Corporate debt securities |  |  |  |  |  |  |  |  |
Maturing in one year or less |  | $ | 69,588 |  | $ | 2 |  | $ | (22 | ) | $ | 69,568 |
Maturing after one year through three years |  | — |  | — |  | — |  | — |
Total corporate debt securities |  | $ | 69,588 |  | $ | 2 |  | $ | (22 | ) | $ | 69,568 |
Total marketable securities |  | $ | 87,841 |  | $ | 9 |  | $ | (28 | ) | $ | 87,822 |
December 31, 2016 |  |  |  |  |  |  |  |  |
Marketable securities |  |  |  |  |  |  |  |  |
U.S. government and municipal obligations |  |  |  |  |  |  |  |  |
Maturing in one year or less |  | $ | 52,754 |  | $ | 5 |  | $ | (12 | ) | $ | 52,747 |
Maturing after one year through three years |  | 296 |  | 8 |  | — |  | 304 |
Total U.S. government and municipal obligations |  | $ | 53,050 |  | $ | 13 |  | $ | (12 | ) | $ | 53,051 |
Corporate debt securities |  |  |  |  |  |  |  |  |
Maturing in one year or less |  | $ | 94,320 |  | $ | — |  | $ | (56 | ) | $ | 94,264 |
Maturing after one year through three years |  | — |  | — |  | — |  | — |
Total corporate debt securities |  | $ | 94,320 |  | $ | — |  | $ | (56 | ) | $ | 94,264 |
Total marketable securities |  | $ | 147,370 |  | $ | 13 |  | $ | (68 | ) | $ | 147,315 |

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration