REVENUE - Affect of Adoption of ASC 606 (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Oct. 01, 2018	Jul. 01, 2018	Jun. 30, 2018
Assets
Prepaid expenses and other current assets	$ 2,871		$ 1,610		$ 2,871	$ 1,610		$ 1,180	$ 929
Other assets	1,903		458		1,903	458		1,974	720
Liabilities
Deferred revenue	1,437	$ 1,428	730		1,437	730	$ 1,428	1,638	511
Equity
Accumulated deficit	(249,349)		(227,829)		(249,349)	(227,829)		(232,372)	(232,748)
Income Statement
License and transaction fees	34,406		31,532		67,928	56,791
Selling, general and administrative	10,931		9,005		20,381	15,929
Net income (loss)	(10,657)	$ (6,320)	(4,194)	$ (2,171)	(16,977)	(6,365)
Calculated under Revenue Guidance in Effect before Topic 606
Assets
Prepaid expenses and other current assets	2,618				2,618				929
Other assets	638				638				720
Liabilities
Deferred revenue	357				357				511
Equity
Accumulated deficit	(249,787)				(249,787)				$ (232,748)
Income Statement
Selling, general and administrative	10,933				20,395
Net income (loss)	(10,694)				(17,037)
Accounting Standards Update 2014-09 | Adjustment
Assets
Prepaid expenses and other current assets	(253)				(253)			251
Other assets	(1,265)				(1,265)			1,254
Liabilities
Deferred revenue	(1,080)				(1,080)		$ 0	1,127
Equity
Accumulated deficit	(438)				(438)			$ 376
Income Statement
Selling, general and administrative	2				14
Net income (loss)	(37)				(60)
License and transaction fees
Income Statement
License and transaction fees	29,837		$ 23,514		58,808	$ 42,911
License and transaction fees | Calculated under Revenue Guidance in Effect before Topic 606
Income Statement
License and transaction fees	29,801				58,761
License and transaction fees | Accounting Standards Update 2014-09 | Adjustment
Income Statement
License and transaction fees	$ (36)				$ (47)