Summary of Significant Accounting Policies - Weighted Average Shares Outstanding for Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Earnings per share — Basic:
Net income	$ (4,242)	$ 4,415	$ 6,081	$ 1,244	$ 3,928	$ 4,824	$ 13,094	$ 2,648	$ 7,498	$ 24,494	$ 2,420
Weighted-average shares outstanding — Basic	65,988	65,493	65,401	65,015	64,749	64,637	64,265	64,019	65,474	64,417	63,435
Net income per common share — Basic	$ (0.06)	$ 0.07	$ 0.09	$ 0.02	$ 0.06	$ 0.07	$ 0.20	$ 0.04	$ 0.11	$ 0.38	$ 0.04
Earnings per share — Diluted:
Net income	$ (4,242)	$ 4,415	$ 6,081	$ 1,244	$ 3,928	$ 4,824	$ 13,094	$ 2,648	$ 7,498	$ 24,494	$ 2,420
Weighted-average shares outstanding — Basic	65,988	65,493	65,401	65,015	64,749	64,637	64,265	64,019	65,474	64,417	63,435
Effect of potentially dilutive securities									138	183	5
Weighted-average shares outstanding — Diluted	65,988	65,664	65,560	65,353	64,917	64,776	64,857	64,054	65,612	64,600	63,440
Net income per common share — Diluted	$ (0.06)	$ 0.07	$ 0.09	$ 0.02	$ 0.06	$ 0.07	$ 0.20	$ 0.04	$ 0.11	$ 0.38	$ 0.04