CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS - FAIR VALUE (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair value hierarchy for financial assets and liabilities
Assets	$ 24,897	$ 89,574
Liabilities	5,636	14,825
Zipsor
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	452	1,489
Lazanda
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	4,219	11,742
CAMBIA
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	965	1,594
Corporate debt securities
Fair value hierarchy for financial assets and liabilities
Assets	2,308	36,850
U.S. Treasury securities
Fair value hierarchy for financial assets and liabilities
Assets	3,605
Money market funds
Fair value hierarchy for financial assets and liabilities
Assets	101	532
Commercial paper
Fair value hierarchy for financial assets and liabilities
Assets	18,883	52,192
Level 1
Fair value hierarchy for financial assets and liabilities
Assets	101	532
Level 1 \| Money market funds
Fair value hierarchy for financial assets and liabilities
Assets	101	532
Level 2
Fair value hierarchy for financial assets and liabilities
Assets	24,796	89,042
Level 2 \| Corporate debt securities
Fair value hierarchy for financial assets and liabilities
Assets	2,308	36,850
Level 2 \| U.S. Treasury securities
Fair value hierarchy for financial assets and liabilities
Assets	3,605
Level 2 \| Commercial paper
Fair value hierarchy for financial assets and liabilities
Assets	18,883	52,192
Level 3
Fair value hierarchy for financial assets and liabilities
Liabilities	5,636	14,825
Level 3 \| Zipsor
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	452	1,489
Level 3 \| Lazanda
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	4,219	11,742
Level 3 \| CAMBIA
Fair value hierarchy for financial assets and liabilities
Liabilities, contingent consideration	$ 965	$ 1,594

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Amount of liability recognized arising from contingent consideration in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

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No definition available.

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Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity.

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