SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Assets:
U.S. treasuries	$ 4,500
Liabilities:
Warrant liability	0	$ 1,500	$ 242
Fair Value, Recurring | Level 1
Assets:
Money market funds	7,232		8,067
U.S. treasuries	4,497
Total	11,729
Liabilities:
Warrant liability			0
Contingent consideration			0
Total			0
Fair Value, Recurring | Level 2
Assets:
Money market funds	0		0
U.S. treasuries	0
Total	0
Liabilities:
Warrant liability			0
Contingent consideration			0
Total			0
Fair Value, Recurring | Level 3
Assets:
Money market funds	0		0
U.S. treasuries	0
Total	$ 0
Liabilities:
Warrant liability			242
Contingent consideration			145
Total			$ 387