2. Investments (Detail - Held-to-Maturity Securities) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short Term Investments [Member] \| Corporate Bond Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cost	$ 24,000	$ 44
Gross Unrealized Gains	9	0
Gross Unrealized Losses	0	0
Fair Value	24,009	44
Short Term Investments [Member] \| Certificates of deposit [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cost	80
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	80
Long Term Investments [Member] \| Corporate Bond Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cost	5,000	5,555
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(287)	(30)
Fair Value	$ 4,713	$ 5,525

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.6)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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