UNAUDITED QUARTERLY DATA - Effect of Restatement on Previously Filed Balance Sheets - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Convertible preferred stock, shares authorized	900,000	900,000	900,000	900,000	900,000	900,000	900,000	900,000	900,000
Convertible preferred stock, shares issued	445,063	445,063	445,063	445,063	445,063	445,063	445,063	445,063	445,063
Convertible preferred stock, shares outstanding	445,063	445,063	445,063	445,063	445,063	445,063	445,063	445,063	445,063
Convertible preferred stock, liquidation preference value	$ 20,111	$ 19,443	$ 19,443	$ 19,109	$ 19,109	$ 18,775	$ 18,775	$ 18,442	$ 18,442
Preferred stock, par value (in dollars per share)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Preferred stock, shares authorized	1,800,000	1,800,000	1,800,000	1,800,000	1,800,000	1,800,000	1,800,000	1,800,000	1,800,000
Preferred stock, shares issued	0	0	0	0	0	0	0	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Common stock, shares authorized	640,000,000	640,000,000	640,000,000	640,000,000	640,000,000	640,000,000	640,000,000	640,000,000	640,000,000
Common stock, shares issued	60,008,481	60,008,481	53,666,718	53,619,898	50,194,731	40,331,645	40,327,675	40,321,941	40,295,425
Common stock, shares outstanding	59,998,811	59,998,811	53,666,718	53,619,898	50,194,731	40,331,645	40,327,675	40,321,941	40,295,425