SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) - Recurring basis - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents:	$ 49,375	$ 6,593
Short-term investments	72,834	22,710
Liabilities
Liabilities	122,209	29,303
Corporate debt securities
Assets
Short-term investments	27,622	21,210
Commercial paper
Assets
Short-term investments	45,212	1,500
Cash
Assets
Cash and cash equivalents:	757	1,025
Money market funds
Assets
Cash and cash equivalents:	18,875	3,565
Corporate debt securities
Assets
Cash and cash equivalents:	6,749	2,003
Commercial paper
Assets
Cash and cash equivalents:	22,994
Level 1
Assets
Cash and cash equivalents:	19,632	4,590
Short-term investments	0	0
Liabilities
Liabilities	19,632	4,590
Level 1 | Corporate debt securities
Assets
Short-term investments	0	0
Level 1 | Commercial paper
Assets
Short-term investments	0	0
Level 1 | Cash
Assets
Cash and cash equivalents:	757	1,025
Level 1 | Money market funds
Assets
Cash and cash equivalents:	18,875	3,565
Level 1 | Corporate debt securities
Assets
Cash and cash equivalents:	0	0
Level 2
Assets
Cash and cash equivalents:	29,743	2,003
Short-term investments	72,834	22,710
Liabilities
Liabilities	102,577	24,713
Level 2 | Corporate debt securities
Assets
Short-term investments	27,622	21,210
Level 2 | Commercial paper
Assets
Short-term investments	45,212	1,500
Level 2 | Cash
Assets
Cash and cash equivalents:	0	0
Level 2 | Money market funds
Assets
Cash and cash equivalents:	0	0
Level 2 | Corporate debt securities
Assets
Cash and cash equivalents:	6,749	2,003
Level 2 | Commercial paper
Assets
Cash and cash equivalents:	22,994
Level 3
Assets
Cash and cash equivalents:	0	0
Short-term investments	0	0
Liabilities
Liabilities	0	0
Level 3 | Corporate debt securities
Assets
Short-term investments	0	0
Level 3 | Commercial paper
Assets
Short-term investments	0	0
Level 3 | Cash
Assets
Cash and cash equivalents:	0	0
Level 3 | Money market funds
Assets
Cash and cash equivalents:	0	0
Level 3 | Corporate debt securities
Assets
Cash and cash equivalents:	$ 0	$ 0