STOCK-BASED COMPENSATION - Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Shares
Options exercised (in shares)	(72,750)	0
Stock Options | The 2004 Plan
Shares
Options outstanding at the beginning of the period (in shares)	30,875
Options granted (in shares)	0
Options exercised (in shares)	0
Options forfeited (in shares)	0
Options expired (in shares)	(10,875)
Options outstanding at the end of the period (in shares)	20,000	30,875
Options vested and expected to vest at the end of the period (in shares)	20,000
Options exercisable at the end of the period (in shares)	20,000
Weighted- Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)	$ 25.71
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	0
Options forfeited (in dollars per share)	0
Options expired (in dollars per share)	20.52
Options outstanding at the end of the period (in dollars per share)	28.54	$ 25.71
Options vested and expected to vest at the end of the period (in dollars per share)	28.54
Options exercisable at the end of the period (in dollars per share)	$ 28.54
Weighted- Average Remaining Contractual Term
Options outstanding at the end of the period	1 year 4 months 24 days
Options vested and expected to vest at the end of the period	1 year 4 months 24 days
Options exercisable at the end of the period	1 year 4 months 24 days
Aggregate Intrinsic Value (in thousands)
Options outstanding at the end of the period	$ 0
Options vested and expected to vest at the end of the period	0
Options exercisable at the end of the period	$ 0
Stock Options | The 2014 Plan
Shares
Options outstanding at the beginning of the period (in shares)	232,956
Options granted (in shares)	2,100,000
Options exercised (in shares)	0
Options forfeited (in shares)	(259)
Options expired (in shares)	(128,856)
Options outstanding at the end of the period (in shares)	2,203,841	232,956
Options vested and expected to vest at the end of the period (in shares)	2,203,841
Options exercisable at the end of the period (in shares)	103,841
Weighted- Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)	$ 36.18
Options granted (in dollars per share)	1.31
Options exercised (in dollars per share)	0
Options forfeited (in dollars per share)	25.73
Options expired (in dollars per share)	44.84
Options outstanding at the end of the period (in dollars per share)	2.45	$ 36.18
Options vested and expected to vest at the end of the period (in dollars per share)	2.45
Options exercisable at the end of the period (in dollars per share)	$ 25.46
Weighted- Average Remaining Contractual Term
Options outstanding at the end of the period	9 years 9 months 18 days
Options vested and expected to vest at the end of the period	9 years 9 months 18 days
Options exercisable at the end of the period	6 years 6 months
Aggregate Intrinsic Value (in thousands)
Options outstanding at the end of the period	$ 1,827
Options vested and expected to vest at the end of the period	1,827
Options exercisable at the end of the period	$ 0
Stock Options | The 2019 Zyla Plan
Shares
Options outstanding at the beginning of the period (in shares)	985,944
Options granted (in shares)	0
Options exercised (in shares)	(72,750)
Options forfeited (in shares)	(402,296)
Options expired (in shares)	(476,340)
Options outstanding at the end of the period (in shares)	34,558	985,944
Options vested and expected to vest at the end of the period (in shares)	34,558
Options exercisable at the end of the period (in shares)	25,029
Weighted- Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)	$ 2.93
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	2.40
Options forfeited (in dollars per share)	2.73
Options expired (in dollars per share)	2.73
Options outstanding at the end of the period (in dollars per share)	3.23	$ 2.93
Options vested and expected to vest at the end of the period (in dollars per share)	3.23
Options exercisable at the end of the period (in dollars per share)	$ 3.23
Weighted- Average Remaining Contractual Term
Options outstanding at the end of the period	7 years
Options vested and expected to vest at the end of the period	7 years
Options exercisable at the end of the period	6 years 7 months 6 days
Aggregate Intrinsic Value (in thousands)
Options outstanding at the end of the period	$ 0
Options vested and expected to vest at the end of the period	0
Options exercisable at the end of the period	$ 54