COLLABORATION AND OTHER AGREEMENTS - Schedule of Deferred Revenue (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total deferred revenue	$ 51,939	$ 56,820
Less: Current portion	(13,627)	(12,350)
Deferred revenue, non-current portion	38,312	44,470
Ono
Disaggregation of Revenue [Line Items]
Total deferred revenue	24,799	27,555
Pierre Fabre
Disaggregation of Revenue [Line Items]
Total deferred revenue	26,098	22,394
Mirati
Disaggregation of Revenue [Line Items]
Total deferred revenue	1,042	2,468
Loxo Oncology
Disaggregation of Revenue [Line Items]
Total deferred revenue	0	2,403
Other partners
Disaggregation of Revenue [Line Items]
Total deferred revenue	0	$ 2,000
BRAFTOVI and MEKTOVI
Disaggregation of Revenue [Line Items]
Total deferred revenue	$ 6,000