FAIR VALUE - Schedule of Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Short-term investments	$ 7,114	$ 0
Recurring
Assets:
Total	20,783	24,073
Liabilities:
Total	953	1,038
Recurring | Contingent consideration—Zipsor
Liabilities:
Contingent consideration liability	417	531
Recurring | Contingent consideration—CAMBIA
Liabilities:
Contingent consideration liability	536	507
Recurring | Corporate
Assets:
Short-term investments	749
Recurring | Money market funds
Assets:
Cash and cash equivalents	123	11
Recurring | Commercial paper
Assets:
Cash and cash equivalents		14,028
Multiple	13,903
Recurring | Collegium warrants
Assets:
Investments	5,307	8,784
Recurring | Agency bond
Assets:
Cash and cash equivalents		1,250
Short-term investments	701
Recurring | Level 1
Assets:
Total	123	11
Liabilities:
Total	0	0
Recurring | Level 1 | Contingent consideration—Zipsor
Liabilities:
Contingent consideration liability	0	0
Recurring | Level 1 | Contingent consideration—CAMBIA
Liabilities:
Contingent consideration liability	0	0
Recurring | Level 1 | Corporate
Assets:
Short-term investments	0
Recurring | Level 1 | Money market funds
Assets:
Cash and cash equivalents	123	11
Recurring | Level 1 | Commercial paper
Assets:
Cash and cash equivalents		0
Multiple	0
Recurring | Level 1 | Commercial paper | Short-term Investments
Assets:
Multiple	8,200
Recurring | Level 1 | Commercial paper | Cash and cash equivalents
Assets:
Multiple	5,700
Recurring | Level 1 | Collegium warrants
Assets:
Investments	0	0
Recurring | Level 1 | Agency bond
Assets:
Cash and cash equivalents		0
Short-term investments	0
Recurring | Level 2
Assets:
Total	20,660	24,062
Liabilities:
Total	0	0
Recurring | Level 2 | Contingent consideration—Zipsor
Liabilities:
Contingent consideration liability	0	0
Recurring | Level 2 | Contingent consideration—CAMBIA
Liabilities:
Contingent consideration liability	0	0
Recurring | Level 2 | Corporate
Assets:
Short-term investments	749
Recurring | Level 2 | Money market funds
Assets:
Cash and cash equivalents	0	0
Recurring | Level 2 | Commercial paper
Assets:
Cash and cash equivalents		14,028
Multiple	13,903
Recurring | Level 2 | Commercial paper | Short-term Investments
Assets:
Multiple	5,700
Recurring | Level 2 | Commercial paper | Cash and cash equivalents
Assets:
Multiple	100
Recurring | Level 2 | Collegium warrants
Assets:
Investments	5,307	8,784
Recurring | Level 2 | Agency bond
Assets:
Cash and cash equivalents		1,250
Short-term investments	701
Recurring | Level 3
Assets:
Total	0	0
Liabilities:
Total	953	1,038
Recurring | Level 3 | Contingent consideration—Zipsor
Liabilities:
Contingent consideration liability	417	531
Recurring | Level 3 | Contingent consideration—CAMBIA
Liabilities:
Contingent consideration liability	536	507
Recurring | Level 3 | Corporate
Assets:
Short-term investments	0
Recurring | Level 3 | Money market funds
Assets:
Cash and cash equivalents	0	0
Recurring | Level 3 | Commercial paper
Assets:
Cash and cash equivalents		0
Multiple	0
Recurring | Level 3 | Commercial paper | Short-term Investments
Assets:
Multiple	5,700
Recurring | Level 3 | Commercial paper | Cash and cash equivalents
Assets:
Multiple	100
Recurring | Level 3 | Collegium warrants
Assets:
Investments	0	0
Recurring | Level 3 | Agency bond
Assets:
Cash and cash equivalents		$ 0
Short-term investments	$ 0